HTTP creds: Fix GUI blocking for 5 seconds when entering wrong password

HTTP creds:  Fix GUI blocking for 5 seconds when entering wrong password

The Qt HTTP thread calls authenticationRequired (indirectly) using a
BlockingQueuedConnection. So when we call invalidateToken from slot
connected to this signal and end up calling QNAM::clearAccessCache which
waits on the thread for 5 seconds

Backtraces:

Qt HTTP thread:
 #0  0x00007ffff20c707f in pthread_cond_wait@@GLIBC_2.3.2 ()
 #1  0x00007ffff43f0c0b in QWaitConditionPrivate::wait
 #2  QWaitCondition::wait
 #3  0x00007ffff43ea06b in QSemaphore::acquire
 #4  0x00007ffff45dcf6f in QMetaObject::activate
[...]
 #9  0x00007ffff45dd607 in QMetaObject::activate
 #10 0x00007ffff4edbaf7 in QHttpNetworkReply::authenticationRequired
 #11 0x00007ffff4e0b2b4 in QHttpNetworkConnectionPrivate::handleAuthenticateChallenge
 #12 0x00007ffff4e10753 in QHttpNetworkConnectionChannel::handleStatus
 #13 0x00007ffff4e11cc9 in QHttpNetworkConnectionChannel::allDone
 #14 0x00007ffff4e14605 in QHttpProtocolHandler::_q_receiveReply

Main Thread:
 #0  0x00007ffff20c7428 in pthread_cond_timedwait@@GLIBC_2.3.2 ()
 #1  0x00007ffff43f0b56 in QWaitConditionPrivate::wait_relative (time=5000, this=0x136c580)
 #2  QWaitConditionPrivate::wait (time=5000, this=0x136c580)
 #3  QWaitCondition::wait (this=this@entry=0x136c788, mutex=mutex@entry=0x136c760, time=time@entry=5000)
 #4  0x00007ffff43efa6e in QThread::wait (this=<optimized out>, time=time@entry=5000)
 #5  0x00007ffff4e1edd3 in QNetworkAccessManagerPrivate::clearCache
 #6  0x00007ffff7b6fb03 in OCC::HttpCredentials::invalidateToken()
 #7  0x000000000057adb4 in OCC::AccountState::slotInvalidCredentials()
 #8  0x000000000057ac76 in OCC::AccountState::slotConnectionValidatorResult(OCC::ConnectionValidator::Status, QStringList const&) ()
 #9  0x00000000005ab45c in OCC::AccountState::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)
 #10 0x00007ffff45dcd30 in QMetaObject::activate
 #11 0x00007ffff7b78671 in OCC::ConnectionValidator::connectionResult(OCC::ConnectionValidator::Status, QStringList) ()
 #12 0x00007ffff7ae2514 in OCC::ConnectionValidator::reportResult(OCC::ConnectionValidator::Status) ()
 #13 0x00007ffff7ae39b7 in OCC::ConnectionValidator::slotAuthFailed(QNetworkReply*) ()
 #14 0x00007ffff7b784a9 in OCC::ConnectionValidator::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) ()
 #15 0x00007ffff45dcd30 in QMetaObject::activate
 #16 0x00007ffff7b766dc in OCC::AbstractNetworkJob::networkError(QNetworkReply*)
 #17 0x00007ffff7af9f6e in OCC::AbstractNetworkJob::slotFinished()
 #18 0x00007ffff7b7654d in OCC::AbstractNetworkJob::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) ()
 #20 0x00007ffff45dd607 in QMetaObject::activate
 #21 0x00007ffff4edd143 in QNetworkReply::finished
 #22 0x00007ffff4e3fec7 in QNetworkReplyHttpImplPrivate::finished
 #23 0x00007ffff4e41818 in QNetworkReplyHttpImpl::close
 #24 0x00007ffff7b7047b in OCC::HttpCredentials::slotAuthentication(QNetworkReply*, QAuthenticator*) ()
 #25 0x00007ffff7b79092 in OCC::HttpCredentials::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) ()
 #27 0x00007ffff45dd607 in QMetaObject::activate
 #28 0x00007ffff4e1d6fb in QNetworkAccessManager::authenticationRequired
 #29 0x00007ffff4e1ea07 in QNetworkAccessManagerPrivate::authenticationRequired
 #30 0x00007ffff4e3c784 in QNetworkReplyHttpImplPrivate::httpAuthenticationRequired

Another case of Main Thread:
 #5  0x00007ffff4e1edd3 in QNetworkAccessManagerPrivate::clearCache
 #6  0x00007ffff7b6fb03 in OCC::HttpCredentials::invalidateToken()
 #7  0x000000000057b1e4 in OCC::AccountState::slotInvalidCredentials() ()
 #8  0x00000000005abb8a in OCC::AccountState::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) ()
 #9  0x00007ffff45dcd30 in QMetaObject::activate
 #10 0x00007ffff7b76ed5 in OCC::Account::invalidCredentials() ()
 #11 0x00007ffff7ad55f5 in OCC::Account::handleInvalidCredentials()
 #12 0x00007ffff7afa69a in OCC::AbstractNetworkJob::slotFinished()
 #13 0x00007ffff7b7654d in OCC::AbstractNetworkJob::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) ()
 #15 0x00007ffff45dd607 in QMetaObject::activate
 #16 0x00007ffff4edd143 in QNetworkReply::finished
 #17 0x00007ffff4e3fec7 in QNetworkReplyHttpImplPrivate::finished
 #18 0x00007ffff4e41818 in QNetworkReplyHttpImpl::close
 #19 0x00007ffff7b7047b in OCC::HttpCredentials::slotAuthentication(QNetworkReply*, QAuthenticator*) ()
 #20 0x00007ffff7b79092 in OCC::HttpCredentials::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) ()
 #22 0x00007ffff45dd607 in QMetaObject::activate
 #23 0x00007ffff4e1d6fb in QNetworkAccessManager::authenticationRequired