Fix gstreamer configuration test.

Don't use gst_is_initialized(). It was added in 0.10.31, but we don't
actually require that version.

Change-Id: If5d662e18511cf636861bf93eeccc1f5b69e26f1
Reviewed-by: Christian Stromme <christian.stromme@theqtcompany.com>

config.tests/unix/gstreamer/gstreamer.cpp

@@ -37,6 +37,5 @@
 
 int main(int, char**)
 {
-    gst_is_initialized();
     return 0;
 }