Use QBasicMutex instead of Q_GLOBAL_STATIC QMutex

Use QBasicMutex instead of Q_GLOBAL_STATIC QMutex

QBasicMutex is a POD and can be used as a static global object.

in qpicture.cpp factoryLoader is used only once, and under the mutex, so
there is no need for Q_GLOBAL_STATIC for it, it can be a function static

in qhostinfo_unix.cpp the code seemed wrong while compiled with
namespace and QT_NO_GETADDRINFO.  I also could get rid of one include
because it was included earlier.

Change-Id: I3c700203c3e067266c20733f4bda8031446dbb86
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>