Fix ceilometer-acompute rejoin problems

The problem was in the screenrc file generated, where the
following command appeared:

sg libvirtd "ceilometer-agent-compute
                 --config-file /etc/ceilometer/ceilometer.conf"^M"

The final "^M" was not then parsed.

Change-Id: Ie6c5b1c9e3d196a3a9c343c2afb46435711c10f5
Closes-bug: #1311666
diff --git a/lib/ceilometer b/lib/ceilometer
index 5030b3c..d024166 100644
--- a/lib/ceilometer
+++ b/lib/ceilometer
@@ -236,7 +236,7 @@
 # start_ceilometer() - Start running processes, including screen
 function start_ceilometer {
     if [[ "$VIRT_DRIVER" = 'libvirt' ]]; then
-        screen_it ceilometer-acompute "cd ; sg $LIBVIRT_GROUP \"ceilometer-agent-compute --config-file $CEILOMETER_CONF\""
+        screen_it ceilometer-acompute "cd ; sg $LIBVIRT_GROUP 'ceilometer-agent-compute --config-file $CEILOMETER_CONF'"
     fi
     if [[ "$VIRT_DRIVER" = 'vsphere' ]]; then
         screen_it ceilometer-acompute "cd ; ceilometer-agent-compute --config-file $CEILOMETER_CONF"