Disable qmacstyle test on Mac OS X

The QMacStyle is not built as part of QtWidgets at the moment (see the
TODO in src/widgets/styles/styles.pri), so disable the test for now.

I've included a comment in styles.pri to re-enable the test once the
style is done.

Change-Id: Ia6ea130135586f107ba257bf2c6c2c7187a830b6
Reviewed-by: João Abecasis <joao.abecasis@nokia.com>

src/widgets/styles/styles.pri

@@ -37,7 +37,7 @@ contains( styles, all ) {
 	styles = mac windows windowsxp windowsvista
 }
 
-# TODO
+# TODO, re-enable qmacstyle in tests/auto/widgets/styles/sytles.pro when done
 styles -= mac
 
 x11{

tests/auto/widgets/styles/styles.pro

@@ -1,6 +1,7 @@
 TEMPLATE=subdirs
 SUBDIRS=\
-   qmacstyle \
+# disabled in src/widgets/styles/styles.pri, so disable the test as well
+#   qmacstyle \
    qstyle \
    qstyleoption \
    qstylesheetstyle \