[CherryPick] [GStreamer] New reference returned by g_main_context_new() must be freed

[CherryPick] [GStreamer] New reference returned by g_main_context_new() must be freed

[Title] [GStreamer] New reference returned by g_main_context_new() must be freed
[Issues] NA
[Problem] Memory leak fix in WebAudio.
[Solution] Cherry picked.
[Cherry-Picker] Praveen R Jadhav <praveen.j@samsung.com>

https://bugs.webkit.org/show_bug.cgi?id=112899

Patch by Sudarsana Nagineni <sudarsana.nagineni@intel.com> on 2013-03-21
Reviewed by Kenneth Rohde Christiansen.

Fix a memory leak by adopting the new reference returned
by g_main_context_new().

No new tests. No change in behavior.

* platform/audio/gstreamer/AudioFileReaderGStreamer.cpp:
(WebCore::AudioFileReader::createBus):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146479 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Conflicts:

	Source/WebCore/ChangeLog

Change-Id: I71dfca2a5634f80235317516c105235725d94045