This reverts commit
e1f5a49c21826590811710f73e37b7b72e256960.
Retrying uploads with insufficent storage errors frequently leads to
high server traffic. See #5537 for links and a sketch of a correct
solution.
bool mayBlacklist =
item._errorMayBeBlacklisted // explicitly flagged for blacklisting
|| (item._httpErrorCode != 0 // or non-local error
- && item._httpErrorCode != 507 // Don't blacklist "Insufficient Storage"
#ifdef OWNCLOUD_5XX_NO_BLACKLIST
&& item._httpErrorCode / 100 != 5 // In this configuration, never blacklist error 5xx
#endif