make rejoin-stack.sh keep the same service tags

Currently rejoin-stack.sh can not keep the same screen service tags
as the first you deploy openstack due to that the stack-screenrc lack
proper command to configure screen's hardstatus. just delete the old
stack-screenrc so that function screen_rc can write proper initialize
command into stack-screenrc.

fix bug 1182597

Change-Id: I4cb4c6ded93a5c7b0bd39d65a754ddf86553463d
Merge "make rejoin-stack.sh keep the same service tags"