Fix tests when having multiple floating pools

Compute API and scenario test fail even though
'floating_network_name' is specified. This patch provides
floating_network_name from tempest.conf as pool, when
create_floating_ip is used.

Change-Id: I2fc7fe59e5e90fb2739dc7eaa3432e7acb967013
Closes-Bug: #1475143
Co-Authored-By: Tom Patzig <tom.patzig@sap.com>
5 files changed