Validate scheme used in urlopen

An invalid url scheme could be used in urlopen in the python k8s
swagger client to violate security.  Validate that the URL is either
http or https and turn off noise from bandit.

Change-Id: I15fe8f9953e526beb25d84895ed3925a758ccda4
Implements: blueprint gate-bandit

magnum/common/pythonk8sclient/client/swagger.py

@@ -17,6 +17,7 @@ import mimetypes
 import random
 import string
 
+from magnum import utils
 from models import *
 
 
@@ -94,11 +95,13 @@ class ApiClient(object):
     else:
       raise Exception('Method ' + method + ' is not recognized.')
 
+    utils.raise_exception_invalid_scheme(url)
+
     request = MethodRequest(method=method, url=url, headers=headers,
                             data=data)
 
     # Make the request
-    response = urllib2.urlopen(request)
+    response = urllib2.urlopen(request) #nosec
     if 'Set-Cookie' in response.headers:
       self.cookie = response.headers['Set-Cookie']
     string = response.read()