Remove NSSConnection from the Python RPC module
NSSConnection was causing a lot of trouble in the past and there is
a lot of logic around it just to make it not fail. What's more,
when using NSS to create an SSL connection in FIPS mode, NSS
always requires database password which makes the `ipa` command
totally unusable.
NSSConnection is therefore replaced with Python's
httplib.HTTPSConnection which is OpenSSL based.
The HTTPSConnection is set up to handle authentication with client
certificate for connections to Dogtag server as RA agent. It allows
to handle client cert/private key in separate files and also
encrypted private key files.
https://fedorahosted.org/freeipa/ticket/5695
Reviewed-By: Jan Cholasta <jcholast@redhat.com>