Testing failure on the primary node is currently disabled due to drbd problems.

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: iustinp

Reviewed-by: schreiberal

Added tests:
- “gnt-cluster getmaster”
- “gnt-cluster version”
- “gnt-instance list”
- “gnt-instance reinstall”

Reviewed-by: schreiberal

- Test “gnt-backup export” and “gnt-backup import”.
- Move “ResolveInstanceName” to qa_utils.py.
- Fix tests for “ganeti-watcher”.
- Make instance shutdown and startup configurable.

Reviewed-by: schreiberal

Reviewed-by: iustin

Reviewed-by: iustinp

- Run “gnt-cluster verify” and “gnt-cluster info” after adding all nodes
- Remove unused --cleanup option
- Remove --verbose option and always print executed SSH commands

Reviewed-by: iustinp