Fix unsafe SSL connection on TrustedFilter

TrustedFilter was using httplib which doesn't check for CAs.
Here the change is using Requests and verifies local CAs by default (or another
one if provided)
This effort is related to CVE 2013-2255.

SecurityImpact

Closes-Bug: #1373993

Change-Id: I0b8e6319a4cc39876b1e396ef705f0fc5def1e44
(cherry picked from commit 30871e8702737edbbfbcbbb5f21858873b37685c)