Revert "engine: Maintain NetworkUser role id for VnicProfileUser"

This reverts commit 20031dd61f6c6517a5e21d38485c3c3b626fd8aa.

The commit is reverted due to a failure to disable triggers on
roles_groups and permissions tables.

Change-Id: Ie6d98bf84d6452cf48872dd0168248498c20851e
Signed-off-by: Moti Asayag <masayag@redhat.com>