Modify deploy/client.py

Modify deploy/client.py

Bug:
1. when ansible_print process encounter runtime error
e.g. ansible.log doesn't exist, whole client.py
process stucks.
2. cobbler status encounters error when deploy timeout
happens.

Solution:
1. add ansible_print process alive check in function
get_installing_progress to exit parent process
when child process encounter runtime error.
2. remove unnecessary code in calling cobbler status
which cause error.

Change-Id: Ie04d45fd612e7273a6d584e3efb69e1506cdd0f9
Signed-off-by: huangxiangyu <huangxiangyu5@huawei.com>