Use exact option name --enabled-disk-templates consistently

It is possible to use both, --enabled-disk-template
(singular) or --enabled-disk-tempaltes (plural),
but the usage of it has been documented and used in QA
inconsistently. This is fixed by this patch now.
Signed-off-by: Helga Velroyen <helgav@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

man/gnt-cluster.rst

@@ -236,7 +236,7 @@ the cluster creation and DRBD support is enabled you might have to
 manually modify the metavg as well.
 
 If you don't want to use lvm storage at all use
-the ``--enabled-disk-template`` option to restrict the set of enabled
+the ``--enabled-disk-templates`` option to restrict the set of enabled
 disk templates. Once the cluster is initialized
 you can change this setup with the **modify** command.
 

qa/qa_instance.py

@@ -1027,7 +1027,7 @@ def TestInstanceCreationRestrictedByDiskTemplates():
   # Setup the cluster with the enabled_disk_templates
   AssertCommand(
     ["gnt-cluster", "modify",
-     "--enabled-disk-template=%s" %
+     "--enabled-disk-templates=%s" %
        ",".join(enabled_disk_templates)],
     fail=False)
 
@@ -1054,7 +1054,7 @@ def TestInstanceCreationRestrictedByDiskTemplates():
     for (enabled, disabled) in [(templates1, templates2),
                                 (templates2, templates1)]:
       AssertCommand(["gnt-cluster", "modify",
-                     "--enabled-disk-template=%s" %
+                     "--enabled-disk-templates=%s" %
                        ",".join(enabled)],
                     fail=False)
       for disk_template in disabled:
@@ -1067,7 +1067,7 @@ def TestInstanceCreationRestrictedByDiskTemplates():
                              set([constants.DT_DISKLESS, constants.DT_BLOCK]) -
                              set(enabled_disk_templates))
     AssertCommand(["gnt-cluster", "modify",
-                   "--enabled-disk-template=%s" %
+                   "--enabled-disk-templates=%s" %
                      ",".join(other_disk_templates)],
                   fail=False)
     CreateInstanceByDiskTemplate(nodes, enabled_disk_templates[0], fail=True)
@@ -1077,6 +1077,6 @@ def TestInstanceCreationRestrictedByDiskTemplates():
 
   # Restore initially enabled disk templates
   AssertCommand(["gnt-cluster", "modify",
-                 "--enabled-disk-template=%s" %
+                 "--enabled-disk-templates=%s" %
                    ",".join(enabled_disk_templates)],
                  fail=False)