This fixes some issues observed in various situations involving
keystone relation removing and rejoining.
- unset external_gateway_info from routers before removing ports
(fix issue with failing to remove routers, ports, and networks
if an external network is attached to the routers)
- check credentials are available before using them in cleanup
- delete the credentials secret on keystone relation broken
- ensure tempest will be re-inited on rejoin keystone relation
- check if keystone is ready as well when setting the schedule
- tidy and remove some unnecessary or dead code
Change-Id: Id3cd9fb26cb7c0d661f11393d58508e50d481df1
0db2a45a44