OMX Hal: depend on libavservices_minijail_vendor.

libminijail_vendor was added so that OMX can depend on
it. However, OMX's dependency is actually through the
library libavservices_minijail.

Bug: 37343418
Test: (sanity) YouTube
Test: dependency error no longer shows when compiling with
  BOARD_VNDK_VERSION := current
Change-Id: Ife1dc09d8d225adf592829da9cf5603f8f543709