Switch to using M2Crypto

This patch uses M2Crypto instead of PyCrypto to perform encryption
and decryption of user authentication information.
remove pbr runtime dependency
Adjust to handle parallel installed packages
Patch to allow building against python-oslo-sphinx

Recently a renaming occured:
https://bugs.launchpad.net/heat/+bug/1277168

The package with the renaming changed is not yet available.