build: Do not redundantly specifiy H.263-related object files for MSMPEG4v*

These are already covered through dependencies specified in configure.
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  build: Do not redundantly specifiy H.263-related object files for MSMPEG4v*

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/h264: avoid using lost frames as references

Fixes Ticket3386

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>