Generate random password for ironic
Generate random password for ironic

Ironic config use default value(PW_PLACEHOLDER) for password.
Other component(ex:Glance) generate random value for password.
This change ironic also use random value for password.

Change-Id: I3af60e7df6e16e13ff73cdbb87bc2293546d88c7
Closes-Bug: #1423035
mahak/packstack,fr34k8/packstack,fr34k8/packstack,xbezdick/packstack,imcsk8/packstack,xbezdick/packstack,xbezdick/packstack,imcsk8/packstack,stackforge/packstack,stackforge/packstack,imcsk8/packstack,openstack/packstack,openstack/packstack,stackforge/packstack,fr34k8/packstack,mahak/packstack,openstack/packstack,mahak/packstack