Implementation of create_subnet() varies in manila-tempest-plugin

There is need of stable implementation of create_subnet().

For the stable implementation of create_subnet() following parameters have
been added:

1. Condition to check empty str_cidr
2. More attributes in case of ipv6
3. Usage of default_subnet_pool

Implements: blueprint tempest-scenario-manager-stable
Signed-off by: Soniya Vyas<svyas@redhat.com>

Change-Id: I855d07272293d209145598e27e82c7837bf0aecb
1 file changed