Fix clear /etc/puppet/puppet.conf issue.

Previously when clicking "Save" button to save puppet configuration,
it will clear /etc/puppet/puppet.conf.
Now fix it as save puppet configuration info into /etc/puppet/puppet.conf.

Change-Id: Idffce430477f9d44d2a8bff12ad518b479e86648
Signed-off-by: hadong <hadong0720@gmail.com>