Use daemon flag only when USE_SCREEN=False

This patch removes the daemon option, when devstack is started
with USE_SCREEN=True.

Change-Id: Ib3b1c0b2abf9111b767b3d557dacdc7a89a38f59
diff --git a/lib/marconi b/lib/marconi
index 473c8cd..143f38a 100644
--- a/lib/marconi
+++ b/lib/marconi
@@ -154,7 +154,12 @@
 
 # start_marconi() - Start running processes, including screen
 function start_marconi {
-    screen_it marconi-server "marconi-server --config-file $MARCONI_CONF --daemon"
+    if [[ ${USE_SCREEN,,} == "false" ]];; then
+        screen_it marconi-server "marconi-server --config-file $MARCONI_CONF --daemon"
+    else
+        screen_it marconi-server "marconi-server --config-file $MARCONI_CONF"
+    fi
+
     echo "Waiting for Marconi to start..."
     if ! timeout $SERVICE_TIMEOUT sh -c "while ! wget --no-proxy -q -O- $MARCONI_SERVICE_PROTOCOL://$MARCONI_SERVICE_HOST:$MARCONI_SERVICE_PORT/v1/health; do sleep 1; done"; then
         die $LINENO "Marconi did not start"