astakos: Use `with' to open file in management command

snf-astakos-app/astakos/im/management/commands/user-set-initial-quota.py

@@ -49,6 +49,7 @@ AddResourceArgs = namedtuple('AddQuotaArgs', ('resource',
                                               'capacity',
                                               ))
 
+
 class Command(BaseCommand):
     help = """Import user quota limits from file or set quota
 for a single user from the command line
@@ -171,12 +172,8 @@ for a single user from the command line
         qh_sync_user(user.id)
 
     def import_from_file(self, location):
-        try:
-            f = open(location, 'r')
-        except IOError, e:
-            raise CommandError(e)
-
         users = set()
+        with open(location) as f:
             for line in f.readlines():
                 try:
                     t = line.rstrip('\n').split(' ')
@@ -190,7 +187,8 @@ for a single user from the command line
                         user = AstakosUser.objects.get(uuid=user)
                         users.add(user.id)
                     except AstakosUser.DoesNotExist:
-                    self.stdout.write('Not found user having uuid: %s\n' % user)
+                        self.stdout.write('Not found user having uuid: %s\n'
+                                          % user)
                         continue
                     else:
                         try:
@@ -198,9 +196,6 @@ for a single user from the command line
                         except Exception, e:
                             self.stdout.write('Failed to policy: %s\n' % e)
                             continue
-
-            finally:
-                f.close()
         qh_sync_users(users)