(#19764) Fix ipaddress issue scanning beyond the first address

Without this patch the refactoring of the ipaddress fact in 0e514b8
changed the determination behavior unintentionally.  This is a problem
because the behavior change caused the setcode block to scan only one
address in the output of ifconfig.  If the first address is a loopback
(127) address, then no additional addresses will be checked.

This patch addresses the problem by restoring the behavior of splitting
the output of `ifconfig` into lines, then scanning each line.  If an
address is matched that begins with 127, then scanning continues.
Otherwise the matched address is determined to be the ipaddress.

The fixture has been extracted from the description of the issue
published in the comment at http://git.io/MbXKEg