openstack-ardana: switch to new gerrit server
openstack-ardana: switch to new gerrit server

Update Gerrit CI scripts to be compatible with the new
version of Gerrit:

 - update Gerrit server host name
 - switch to HTTP basic authentication, because support
 for HTTP Digest authentication was removed in Gerrit 2.14 [1]

[1] https://github.com/dpursehouse/pygerrit2#usage

gosipyan/automation,aspiers/automation,SUSE-Cloud/automation,SUSE-Cloud/automation,gosipyan/automation,SUSE-Cloud/automation,aspiers/automation,gosipyan/automation,aspiers/automation,gosipyan/automation,aspiers/automation,SUSE-Cloud/automation