Bug 1372051 - Remove external media tests from mach modules. r=gps

MozReview-Commit-ID: BleMN1TMSVa

--HG--
extra : rebase_source : 94f147330a694026e972ead85fd2676f2eb265dc

build/mach_bootstrap.py

@@ -38,7 +38,6 @@ MACH_MODULES = [
     'build/valgrind/mach_commands.py',
     'devtools/shared/css/generated/mach_commands.py',
     'dom/bindings/mach_commands.py',
-    'dom/media/test/external/mach_commands.py',
     'layout/tools/reftest/mach_commands.py',
     'python/mach_commands.py',
     'python/mach/mach/commands/commandinfo.py',