For historical reasons, the migration script looks for the certificates in
a RHEL-$DISTRIBUTION directory (where $DISTRIBUTION is 5 or 6).  The 
subscription-manager-migration package does not require the 
subscription-manager-migration-data package because the migration-data
package is RHEL only and cannot be included in Fedora.  We intentionally
omitted the dependency so that subscription-manager would have the option
of being included in Fedora.

As a consequence, we can't rely on RPM to enforce version requirements
so the migration-data needs to remain backwards compatible.  Thus, I added
some hacks to the spec and make files to support the RHEL-$DISTRIBUTION
convention (even though all the certificates are stored in the RHEL directory).
The result is that you must supply a value for the RHEL_VER variable to make
when you run 'make install'.  The spec file supplies this value by using the
%{rhel} macro.  This macro is not defined on Fedora.  If you need to build
on Fedora (for some reason), you can supply the macro with tito by using the
--rpmbuild-options argument combined with rpmbuild's --define argument.

For example:

  tito build --test --rpm --rpmbuild-options="--define 'rhel 6'"

This example defines the %{rhel} to be 6.
