A user will be able to specify which values should not be included in
tempest configuration file through --remove argument.
For ommiting value(s):
--remove section.key=value[,value2[...]]
For ommiting all values in section.key:
--remove section.key
Patch removes network.remove-extension option, because the patch is more
generic solution of the same issue.
Change-Id: I0375f2bbfa3bb7db4f9b81ea1518e86d725c30a3
3deb8061aa