qtbase: move gstreamer dependency to qtwebkit and blacklist gstreamer 0.10

We don't need qtbase to depend on gstreamer as it doesn't gives us anything valuable.
qtwebkit is the one which needs gstreamer to be installed in sysroot for automatic
detection. Furthermore we're not going to use gstreamer 0.10 so we simply blacklist
it in our distro configuration.

Signed-off-by: Simon Busch <morphis@gravedo.de>