Fix lorax patching logic
Check if pkglist file exists and is not empty
Makefile changes to get things building

-Add dependecy RPMs to makefile for buliding
-Use the local yum repo as the REPO_URL
-Change repo name in mock template to rhel-repo
Fix issue where make incorrectly thought files were modified in packages

Git does not keep track of file stamps, so make thought that
the Makefile target needed to be called. We now diff the Makefile
output from gen-makefile-from-src-rpm.sh and use that to determine
if make needs to be rerun.
Add an EXCLUDE_PKGS variable to makefile to list packages not to build

Rather than deleting a package directory, we have added a variable
to list packages that should not be built.