Ensure server's SSL cert is validated

A bug was introduced which meant that the server SSL certificate was
not being verified. Here we make sure that it is checked (unless
the --insecure flag is used).

Helps guard against man-in-the-middle attack.

Change-Id: I08f30bf3906b6580c871729311343fa8eefda91b
Closes-bug: #1357430

glanceclient/common/https.py

@@ -77,7 +77,8 @@ class HTTPSAdapter(adapters.HTTPAdapter):
 
     def cert_verify(self, conn, url, verify, cert):
         super(HTTPSAdapter, self).cert_verify(conn, url, verify, cert)
-        conn.insecure = not verify
+        conn.ca_certs = verify[0]
+        conn.insecure = verify[1]
 
 
 class HTTPSConnectionPool(connectionpool.HTTPSConnectionPool):