Maintenance-mode development.

- [NC] Complete setup of automated handling of migration credentials.

Implements EUCA-5096, EUCA-5098.
Merge remote-tracking branch 'origin/testing' into dev/juphoff/evac-test
Maintenance-mode development.

- [CC] Add caching of migrationCapable information from NCs.

Implements EUCA-5100.
Merge branch 'dev/juphoff/evac-test' of git.eucalyptus-systems.com:eucalyptus into dev/juphoff/evac-test
Merge remote-tracking branch 'origin/testing' into dev/juphoff/evac-test
Maintenance-mode development.

- [CC] Honor NC migration capability when scheduling.

Implements EUCA-5100.
Merge remote-tracking branch 'origin/testing' into dev/juphoff/evac-test