Move static-inventory option into parser group

Static-inventory should not be in extra_vars_group, this
patch move this option into parser.
It's faling when we want to provide both:
--static-inventory and --extra-vars option since the
extra_vars_group is mutually exclusive.

Change-Id: I973ea8c210db477b735a99755332346a646bea19
(cherry picked from commit 986f926111)

tripleoclient/v1/tripleo_validator.py

@@ -254,6 +254,18 @@ class TripleOValidatorRun(command.Command):
                 " run invocation. For example: --limit \"compute-0,"
                 " compute-1, compute-5\".")
         )
+
+        parser.add_argument(
+            '--static-inventory',
+            action='store',
+            default='',
+            help=_(
+                "Provide your own static inventory file. You can generate "
+                "such an inventory calling tripleo-ansible-inventory command. "
+                "Especially useful when heat service isn't available."
+            )
+        )
+
         extra_vars_group = parser.add_mutually_exclusive_group(required=False)
 
         extra_vars_group.add_argument(
@@ -292,17 +304,6 @@ class TripleOValidatorRun(command.Command):
                 "will override the other(s)")
         )
 
-        extra_vars_group.add_argument(
-            '--static-inventory',
-            action='store',
-            default='',
-            help=_(
-                "Provide your own static inventory file. You can generate "
-                "such an inventory calling tripleo-ansible-inventory command. "
-                "Especially useful when heat service isn't available."
-            )
-        )
-
         ex_group = parser.add_mutually_exclusive_group(required=True)
 
         ex_group.add_argument(