Fix compilation of MinGW-w64 4.7

Change-Id: Ieab538a077351549727c94dad17d4d77ab492a97
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>

src/libs/utils/savefile.cpp

@@ -88,7 +88,7 @@ bool SaveFile::commit()
         return false;
     }
 #ifdef Q_OS_WIN
-    FlushFileBuffers(handle());
+    FlushFileBuffers(reinterpret_cast<HANDLE>(handle()));
 #else
     fdatasync(handle());
 #endif