Improve shell cmds and logging in 'delete_vips'

Get rid of piping to 'grep' in 'ip_address_show'
method and fix issues with logging.

Change-Id: Icbfba0fce437001ba9c4c6c07a0811f49654dfd5
Closes-bug: #1390159
Merge "Improve shell cmds and logging in 'delete_vips'"