Change a Stagefright assert to an error check.

During OMX codec initialization it is possible that buffer allocation
fails.  This changes Stagefright to set an error state and abort
initialization rather than crashing with an assert failure when that
happens.

Change-Id: I2fc2fadfe75657cdbf649cc8cafd2e4c251a5f8b
Bug: 3282700
diff --git a/media/libstagefright/OMXCodec.cpp b/media/libstagefright/OMXCodec.cpp
index 69ab75a..352f9fb 100644
--- a/media/libstagefright/OMXCodec.cpp
+++ b/media/libstagefright/OMXCodec.cpp
@@ -1536,7 +1536,9 @@
     }
 
     err = allocateBuffers();
-    CHECK_EQ(err, (status_t)OK);
+    if (err != (status_t)OK) {
+        return err;
+    }
 
     if (mQuirks & kRequiresLoadedToIdleAfterAllocation) {
         err = mOMX->sendCommand(mNode, OMX_CommandStateSet, OMX_StateIdle);