gnt-cluster info: show more cluster parameters

Even if we cannot modify all of them, they are useful information about
the current cluster.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

scripts/gnt-cluster

@@ -243,6 +243,10 @@ def ShowClusterConfig(opts, args):
 
   ToStdout("Cluster parameters:")
   ToStdout("  - candidate pool size: %s", result["candidate_pool_size"])
+  ToStdout("  - master netdev: %s", result["master_netdev"])
+  ToStdout("  - default bridge: %s", result["default_bridge"])
+  ToStdout("  - lvm volume group: %s", result["volume_group_name"])
+  ToStdout("  - file storage path: %s", result["file_storage_dir"])
 
   ToStdout("Default instance parameters:")
   for gr_name, gr_dict in result["beparams"].items():