Verify more information in API tests for LBaaS

In API tests for LBaaS not all information is checked  that is
required.
For example, test_show_* checks only equality of name and id;
test_associate_disassociate_health_monitor_with_pool does not check
that pool containts healthmonitor after assosiating.

This tests should be corrected.

Also create_member and update_member was updated to use _create and
_update from network_client_base.

Closes-bug: #1262112

Change-Id: I352253ce9e28b46324a81e40c6b86759e0687420
Merge "Verify more information in API tests for LBaaS"