Make ZeroMQ based RPC consumer threads more robust

Consumers could potentially raise an uncaught exception
and exit prematurely.

Related to bug 1189711

Change-Id: I9cb32d8530f3a1dd623e193476e02b990b40b466
exception: remove

This patch drops the obsolete openstack.common.exception module.

Most project should define their own exception based on their API and
the context they evolve in. Many projects don't use this, only neutron,
cinder and heat used it. I've copy pasted the few exceptions that they
were using, but that's still by far less code than this whole file.
Ultimately that will let them a chance to remove or shring their own
exception.py. I don't think most projects should have one anyway.

Change-Id: Ia8b2b29bd443233def324e97de7342c2634bccff
Closes-Bug: #1208734
Bump hacking to 0.7.0

Fixes H202, H602 errors

Change-Id: Ic3045f15116d1d7a28b63bc94a0a341b9304ffdd
Merge "Make ZeroMQ based RPC consumer threads more robust"