specify session name on perform rejoin stack

rejoin-stack.sh would not specify screen session name which will lead
unstack.sh unable to kill the screen session started by rejoin-stack.sh
after hypervisor rebooted. So specify the session name if
rejoin-stack.sh need to start a new sreen session.

fixes bug 1182806

Change-Id: I68635887aa82fa63f3667e0f090ea2836eec7b68

rejoin-stack.sh

@@ -5,13 +5,15 @@
 
 TOP_DIR=`dirname $0`
 
+source $TOP_DIR/stackrc
+
 # if screenrc exists, run screen
 if [[ -e $TOP_DIR/stack-screenrc ]]; then
     if screen -ls | egrep -q "[0-9].stack"; then
         echo "Attaching to already started screen session.."
         exec screen -r stack
     fi
-    exec screen -c $TOP_DIR/stack-screenrc
+    exec screen -c $TOP_DIR/stack-screenrc -S $SCREEN_NAME
 fi
 
 echo "Couldn't find $TOP_DIR/stack-screenrc file; have you run stack.sh yet?"

stack.sh

@@ -125,7 +125,6 @@ fi
 # and the specified rpc backend is available on your platform.
 check_rpc_backend
 
-SCREEN_NAME=${SCREEN_NAME:-stack}
 # Check to see if we are already running DevStack
 # Note that this may fail if USE_SCREEN=False
 if type -p screen >/dev/null && screen -ls | egrep -q "[0-9].$SCREEN_NAME"; then

stackrc

@@ -245,6 +245,9 @@ PUBLIC_NETWORK_NAME=${PUBLIC_NETWORK_NAME:-"public"}
 # Compatibility until it's eradicated from CI
 USE_SCREEN=${SCREEN_DEV:-$USE_SCREEN}
 
+# Set default screen name
+SCREEN_NAME=${SCREEN_NAME:-stack}
+
 # Local variables:
 # mode: shell-script
 # End: