Port mod_repo and helpers from yumpkg.py to yumpkg5.py, Fix #5282
Port more functions from yumpkg.py to yumpkg5.py
Import OS
Import mod_repo funcs from salt.modules.yumpkg instead
Re-namespace the imports from yumpkg.py
Merge pull request #5546 from basepi/pkgrepo5282

Make pkgrepo work for RHEL5 (yumpkg5.py), Fix #5282