Currently the build without implicitly included precompiled header
is not supported anyway (because Qt MOC source files do not include
stdafx.h, they include plain headers).
So when we decide to support building without implicitly included
precompiled headers we'll have to fix all the headers anyway.
First try to activate Qt OpenSSL usage and let Qt to set
the locking methods for OpenSSL. Only if Qt didn't set them
we use our own locking methods. Before that we were always
setting our own locking methods and Qt was overriding them
at some random moment of time sometimes leading to a crash.
