Add list-networks test for os-networks API

Adds a test to list networks for a non-admin tenant
using the compute os-networks API.

For Flat* network managers in nova, a tenant is not
assigned to a network so this tests that when listing
networks with a non-admin tenant, we get something back
since the underlying code in nova should pass 'allow_none'
to the DB API when listing the networks for Flat and
FlatDHCP network managers.

Change-Id: I5c50607279a8a385ebe96bf498e3e95079d6dec1
Related-Bug: #1327406
Fix the flavor ram string value

Current test_create_flavor_using_string_ram specify " 1024 " as the
ram string value and the spaces are meaningless.
Current Nova API(v2.0) validation is loose and the API accepts this
value. However, new API(v2.1) will not allow this kind of value.
This patch removes these spaces from the test.

Change-Id: Ifaabcf04e2600bcec8043c981e320d47d8dc6379
Correct docstring indentation

Change-Id: Ifb4ad284f2a36eb6ab42ae2f344f030215186d69
Merge "Add list-networks test for os-networks API"
Merge "Fix the flavor ram string value"
Merge "Correct docstring indentation"
Merge branch 'master' of https://github.com/openstack/tempest