Fix regular expression for finding IP in ha_delete_vips test

The test searchs for secondary IP address and deletes it.
In order to find ip it parses output of 'ip address show'
command using reqular expression. Old one finds
not a secondary ip address but first in a string.
The new one a bit smarter.

Change-Id: I345e151c8d2cc0083bc0b1e6bb8691969778a84f
Merge "Fix regular expression for finding IP in ha_delete_vips test"