Remove unused openstack.common modules

They are not used in horizon code base and out-of-date for a long time.
It is time to remove them.
- notifier and rpc graduated oslo-incubator and are distirubted as a
  separate module (oslo.messaging).
- uuidutils is now deprecated in oslo and standard uuid module is
  recommended to use.
- For other modules, we can re-add them if they becomes needed.

Partial-Bug: #1296337
Change-Id: I7cb569954384fd39e9f91316f5e22ca63f4a00ee
Merge "Remove unused openstack.common modules"