Avoid null pointer dereference

on failed call to convertMetaDataToMessage(), return NULL instead
of assigning a null and proceeding with routine.

Bug: 229522006
Test: re-run clusterfuzz case from bug
Change-Id: I9bf705a4f543011cc35505b34dbd664f1f40f80f
(cherry picked from commit 7c9c49ee3edc9e618a42300bec093839fa8a69e6)
Merged-In: I9bf705a4f543011cc35505b34dbd664f1f40f80f
1 file changed