066c71219d2be24e04691221d30ac8c345c588ec
The abandon and restore routines can fail if the change is in the wrong state (abandoned already, or open still). These failure lead to internal NPEs. Instead, create a new exception and give a reason for the failure to the user. Change-Id: Id7861d75e535c439c12329f7e891797c5b1f6eca
Description
RETIRED, Gerrit as used by OpenStack