Fix Occasional test_one_network_label_exact Fail

fixes the occasional tox failure for test_one_network_label_exact by
saving and restoring the original conf values before every test.

see bug details for more information.

Closes-Bug: #1272806

Change-Id: Ib051b5325c0914f2ab3bc293b0052abe8257996d
Merge "Fix Occasional test_one_network_label_exact Fail"