tests: fix up mpg123 test a little
- dist input files - fix sample leak - simplify check for elements - only run mpg123 test if mpg123 is available and selected - fix build in uninstalled setup https://bugzilla.gnome.org/show_bug.cgi?id=686595
- tests/check/Makefile.am 8 additions, 1 deletiontests/check/Makefile.am
- tests/check/elements/.gitignore 1 addition, 0 deletionstests/check/elements/.gitignore
- tests/check/elements/mpg123audiodec.c 11 additions, 50 deletionstests/check/elements/mpg123audiodec.c
- tests/files/Makefile.am 4 additions, 1 deletiontests/files/Makefile.am