Fix MSVC-warnings about unsafe bool operations in tst_qcamera.cpp.

qglobal.h(501) : warning C4804: '-' : unsafe use of type 'bool' in operation
global/qglobal.h(501) : warning C4800: 'int' : forcing value to bool 'true' or 'false' (performance warning)
tst_qcamera.cpp(507) : see reference to function template instantiation 'T qAbs<bool>(const T &)' being compiled

Change-Id: Ifd467b5536a0d386f592ae339129b3ebfb7b8838
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>
Fix MSVC-warning about truncation of constant in tst_qaudiobuffer.cpp.

Change-Id: If9e239be38f8d15542ab9bf3a74bccf0a43b4e69
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>