ext/mpeg2dec/gstmpeg2dec.c: Fix minor memleak when creating pads from static pad...

ext/mpeg2dec/gstmpeg2dec.c: Fix minor memleak when creating pads from static pad templates (#369627).

Original commit message from CVS:
Patch by: Sebastian Dröge  <slomo@circular-chaos.org>
* ext/mpeg2dec/gstmpeg2dec.c: (gst_mpeg2dec_init):
Fix minor memleak when creating pads from static pad templates (#369627).
* tests/check/Makefile.am:
* tests/check/elements/.cvsignore:
* tests/check/elements/mpeg2dec.c: (setup_mpeg2dec),
(cleanup_mpeg2dec), (GST_START_TEST), (mpeg2dec_suite), (main):
Add unit tests for mpeg2dec (#369627).