Add test to serialize and deserialize exceptions
Add test to serialize and deserialize exceptions

Every subclass of HeatException is serialized and then deserialized.
For those classes which don't have a special init method, a generic
inspection is done to test each class. There are four exceptions
that are different, so their arguments are manually constructed.

Change-Id: I9bb21d134f8997c478cd4ee8ef0031e03b053204
Closes-Bug: #1304743

jasondunsmore/heat,openstack/heat,dims/heat,dragorosson/heat,steveb/heat,dims/heat,pratikmallya/heat,noironetworks/heat,cryptickp/heat,rh-s/heat,gonzolino/heat,openstack/heat,takeshineshiro/heat,gonzolino/heat,cwolferh/heat-scratch,rh-s/heat,cwolferh/heat-scratch,pratikmallya/heat,maestro-hybrid-cloud/heat,redhat-openstack/heat,srznew/heat,noironetworks/heat,jasondunsmore/heat,steveb/heat,pshchelo/heat,takeshineshiro/heat,rdo-management/heat,pshchelo/heat,cryptickp/heat,rdo-management/heat,miguelgrinberg/heat,dragorosson/heat,srznew/heat,maestro-hybrid-cloud/heat,miguelgrinberg/heat,redhat-openstack/heat