Add initial support for building in a RHEL 7 mock

Building in an x86_64 mock, since RHEL has not yet provided a 32-bit release.
Merge pull request #157 from mckern/add-el7-to-2.4.x

Add initial support for building in a RHEL 7 mock
maint - update changelog
Merge branch 'master' into 2.4.x