Bug 904258 Fix l10n mozconfigs not to use hgtool for pulling repos, and fix the mac L10n mozconfig not to do a universal build. r=rail,a=Standard DONTBUILD

--HG--
rename : build/client.py-args => build/client.py-l10n-args
rename : mail/config/mozconfigs/macosx-universal/l10n-mozconfig => mail/config/mozconfigs/macosx64/l10n-mozconfig
Bug 909180 - Add client.py-l10n-args to check-sync-exceptions. r=Callek,a=Standard8 DONTBUILD