Bug 980186. Tell automation.environment about the debugger. r=jgriffin

This lets it set the crash reporting envs properly.

--HG--
rename : python/mozbuild/mozbuild/test/frontend/data/test-manifest-install-subdir/subdir.ini => python/mozbuild/mozbuild/test/frontend/data/test-manifest-empty/empty.ini
rename : python/mozbuild/mozbuild/test/frontend/data/test-manifest-install-subdir/moz.build => python/mozbuild/mozbuild/test/frontend/data/test-manifest-empty/moz.build
extra : rebase_source : 1e4cbc0dedab57629e120c4d35bd8270c4f44892