Remove `become: true` from the inventory script

Most validations don't need to be run as root and those that do can
opt-in by saying `become: true` per validation or task.

Change-Id: Iade6ba1302af11e9790719ab0fd3193dc671ffba

scripts/tripleo-ansible-inventory

@@ -104,7 +104,6 @@ class TripleoInventory(object):
                 'hosts': ['localhost'],
                 'vars': {
                     'ansible_connection': 'local',
-                    'ansible_become': True,
                 },
             }
         }
@@ -127,7 +126,6 @@ class TripleoInventory(object):
                 'vars': {
                     # TODO(mandre) retrieve SSH user from heat
                     'ansible_ssh_user': 'heat-admin',
-                    'ansible_become': True,
                 }
             }