Auto merge of #3311 - alexcrichton:fix-nightlies, r=brson

Link OpenSSL statically on OSX

Now that Cargo requires OpenSSL >= 1.0.1 transitively through the `openssl-sys`
0.9 release the dynamic libraries for OpenSSL are no longer located on OSX by
default. This means that the support necessary for libssh2 needs to be
statically linked rather than dynamically linked.

Closes #3303