Update build_spacewalk_baseline

rhn channel names are reserved by redhat. rename channel to start with 'rhel'. This is a better place to do this as we wont need to edit both spacewalk-create-yumrepo.py and spacewalk-orgclone-channel.py
Merge pull request #7 from dodwmd/master

Update build_spacewalk_baseline: New Red Hat basechannel should be renamed to "rhel" (instead of rhn).