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
MCO-174 update wording about wroking version of use_reply_exchange

`rabbitmq.use_reply_exchange` was broken in 2.3.3 and 2.4.0.

A fix is targeted for 2.4.1 and it shouldn't regress.
Merge pull request #160 from richardc/mco-174

MCO-174 update wording about wroking version of use_reply_exchange
maint - update changelog
Merge branch 'master' into 2.4.x