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.
Issue #25: fix bootstrap.sh to work for RHEL7

- Remove pungi from list of host dependencies
in the Makefile (the host dependencies are
fulfilled in order to build pungi itself
so pungi should not be included in this list)
- Remove the host_packages directory (the
copies of rpms therein are no longer needed
now that the epel repo is being enabled)
- RHEL no longer has an optional channel, so
we remove the section which subscribes to the
optional repo
- Pipe out epel repo config with generic url
so that the latest epel-release is always
installed, then enable the epel repo
- Install packages which are not included in
the default RHEL build (now installable via
yum install because epel repo is enabled)
Issue #19: Change foo variable to user_input in bootstrap.sh