Remove networking-ansible from tempest plugins list

This commit removes x/networking-ansible from the tempest plugins list.
The original patch[0] was abandoned because networking-ansible took a
different approach[1] for the testing. So, it's not a tempest plugin
anymore.

[0] https://review.opendev.org/#/c/634647/
[1] https://review.opendev.org/#/c/634918/

Change-Id: I554c438f27a7032f31e56eac2aac110e08bb3d7d
2 files changed