fixed calling of method that never existed

When setting an instance as the primary instance project directory
creation may be necessary. Do not perform this action if instance is
secondary.

awx/main/management/commands/update_instance.py

@@ -54,7 +54,8 @@ class Command(BaseCommandInstance):
         instance.save()
 
         # If this is a primary instance, update projects.
-        self.update_projects_if_primary(instance)
+        if self.is_option_primary():
+            self.update_projects(instance)
 
         # Done!
         print('Successfully updated instance role %s' % instance_str(instance))