fix saltenv for aptpkg.mod_repo from pkgrepo state

so that when key_url=salt://gpg.key, salt will get gpg.key from the correct
environment instead of the 'base' environment.
Merge branch 'fix-mod_repo-saltenv' of git://github.com/bbinet/salt into bbinet-fix-mod_repo-saltenv

Conflicts:
	salt/states/pkgrepo.py