Use HOST_IP instead of SERVICE_HOST for heat API conf

Heat config values heat_metadata_server_url, heat_waitcondition_server_url and
heat_waitcondition_server_url currently derive their host from devstack
SERVICE_HOST. In gating this is set to 127.0.0.1, which would explain why
nova servers are not reaching heat with waitcondition signalling.

This change uses HOST_IP as the default instead of SERVICE_HOST.

Change-Id: I373b086e3a36a3484cfd34f0d1c8c168ac6d465d
Fix Swift process kill

stop_swift() was not killing all swift processes properly.  Change to
manually clean up all screen services with pkill.

Closes-bug: 1268794
Change-Id: Ibb7a2e0dd10a313609f05963264087f82f6f00e2
Merge "Fix Swift process kill"