Restore previous choices, clean up some minor things

awx/main/constants.py

@@ -14,7 +14,7 @@ __all__ = [
 CLOUD_PROVIDERS = ('azure_rm', 'ec2', 'gce', 'vmware', 'openstack', 'rhv', 'satellite6', 'cloudforms', 'tower')
 SCHEDULEABLE_PROVIDERS = CLOUD_PROVIDERS + ('custom', 'scm',)
 PRIVILEGE_ESCALATION_METHODS = [
-    ('', _('None')), ('enable', _('Enable')), ('doas', _('Doas')),
+    ('enable', _('Enable')), ('doas', _('Doas')),
     ('sudo', _('Sudo')), ('su', _('Su')), ('pbrun', _('Pbrun')), ('pfexec', _('Pfexec')),
     ('dzdo', _('DZDO')), ('pmrun', _('Pmrun')), ('runas', _('Runas'))]
 ANSI_SGR_PATTERN = re.compile(r'\x1b\[[0-9;]*m')

awx/main/fields.py

@@ -714,7 +714,7 @@ class CredentialTypeInputField(JSONSchemaField):
             if field['type'] == 'become_method':
                 if not model_instance.managed_by_tower:
                     raise django_exceptions.ValidationError(
-                        _('{0} is a reserved type name'.format(field['type'])),
+                        _('become_method is a reserved type name'),
                         code='invalid',
                         params={'value': value},
                     )

awx/main/migrations/_credentialtypes.py

@@ -200,6 +200,6 @@ def add_azure_cloud_environment_field(apps, schema_editor):
 
 
 def remove_become_methods(apps, schema_editor):
-    become_credtype = CredentialType.objects.get(kind='ssh')
+    become_credtype = CredentialType.objects.get(kind='ssh').first()
     become_credtype.inputs = CredentialType.defaults.get('ssh')().inputs
     become_credtype.save()

awx/main/models/credential/__init__.py

@@ -165,7 +165,7 @@ class V1Credential(object):
             max_length=32,
             blank=True,
             default='',
-            choices=PRIVILEGE_ESCALATION_METHODS,
+            choices=[('', _('None'))] + PRIVILEGE_ESCALATION_METHODS,
             help_text=_('Privilege escalation method.')
         ),
         'become_username': models.CharField(