Enhance watchdog_setup

A tool called "watchdog_setup" has been used to create a simple test
cluster environment on localost for developing and testing
Pgpool-II. It allows to create 3 watchdog node and 3 PostgreSQL server
configuration by single command for example:

$ watchdog_set -wn 3 -n 3

The command is also used in our regression test.

One of the things that watchdog_setup does not support is, assigning
VIP. This is a limitation by deign as it runs on a single
host. However, I would like to test whether watchdog properly executes
if_up_cmd or if_down_cmd, which could increase the test coverage. In
the attached patch, a new option "-vip [ip]" is added to
watchdog_setup. If ip is omitted, '127.0.0.1' is assumed.
The parameters added by this option are followings:

delegate_ip = '127.0.0.1'
if_up_cmd = '/usr/bin/echo "if_up_cmd executed"'
if_down_cmd = 'usr/bin/echo "if_down_cmd executed"'
arping_cmd = '/usr/bin/true'

Comments and suggestions are welcome.

Best regards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp