Fixed a media server crash due to unintialized mRecord member variable

mRecord is not properly initialized if the call to AudioRecord::getMinFrameCount() fails.
media server crashes when the unintialized mRecord object is deleted in AudioSource's destructor.

Change-Id: Ia89222789d044c11c9957a99725bc89f9c709e17

related-to-bug: 6744014
1 file changed