When abort, xcatha.py exit with exit code zero; non-zero is expected

[neo954]

This bug is against xcatha.py commit 6e4c13e.

A process is considered to have completed correctly if its exit code was zero. Otherwise, a non-zero exit code is expected.

# xcatha.py -s -p /media/u/gongjie/ha-test -i eth0:99 -v 10.3.1.99 -m 255.0.0.0 -n c910f03c01p99 -t sqlite
2018-06-13 01:54:34,851 - INFO - Setup this node as xCAT HA standby MN
2018-06-13 01:54:34,852 - INFO - ===> Check virtual ip stage <===
2018-06-13 01:54:34,852 - DEBUG - ping -c 1 -w 10 10.3.1.99
PING 10.3.1.99 (10.3.1.99) 56(84) bytes of data.
64 bytes from 10.3.1.99: icmp_seq=1 ttl=64 time=0.016 ms

--- 10.3.1.99 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.016/0.016/0.016/0.000 ms
2018-06-13 01:54:34,855 - ERROR - Aborted startup as virtual ip appears to be already active.
2018-06-13 01:54:34,855 - ERROR - ===> Check virtual ip stage <===
2018-06-13 01:54:34,855 - ERROR - Error encountered, starting to clean up the environment
2018-06-13 01:54:34,870 - INFO - ===> Configure hostname stage <===
2018-06-13 01:54:34,872 - DEBUG - hostname c910f03c01p07 [Passed]
2018-06-13 01:54:34,872 - INFO - ===> Unconfigure shared data directory stage <===
2018-06-13 01:54:34,872 - INFO - ===> Remove virtual IP stage <===
2018-06-13 01:54:34,874 - DEBUG - ifconfig eth0:99 0.0.0.0 0.0.0.0 &>/dev/null [Failed, OK to ignore]
2018-06-13 01:54:34,877 - DEBUG - ip addr show |grep 10.3.1.99 &>/dev/null [Failed, OK to ignore]
2018-06-13 01:54:34,877 - INFO - Remove virtual IP [Passed]
# echo $?
0

[neo954]

Refer to xcat2/xcat2-task-management#163

[bybai]

Plan to fix it later.