This change adds a new config param ssl_assert_hostname. Its value will
be ultimately passed to the underlying urllib3 param "assert_hostname".
Technically, the value coud be bool or string. This patch focuses to set
it to False to disable hostname check while keeping other cert
verifications.
Change-Id: I8b1ef5fe915d8317f65ce5e1927eb71141027e16
(cherry picked from commit 5d408a01f85b18466b4034d2c38c582b79d2f604)
398346754e