Add delete_net_interface function

This commit adds a new function that deletes a specific
tap device. This bug fix is targeted for Havana.

Change-Id: I26be5d94550db35358caae642fb9000953346826
fixes: bug #1138408
Merge "Add delete_net_interface function"
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp