stagefright: OMXCodec: free allocated port-buffers if init fails

If an error is encountered while allocating port buffers, init
would fail and buffers already allocated would not be freed.
Move OMXCodec to ERROR state and explicitly stop omx component,
hence forcing free-ing up of allocated buffers.
Also defer setting port-status to ENABLED only after having
moved the component to IDLE and add graphicBuffer to port-
buffers-list only if setBuffer is successful.

Change-Id: I54ffb2a299376bf1716473e94948c36648d24b92
CRs-Fixed: 610702

Conflicts:
	media/libstagefright/OMXCodec.cpp