Add eval message when setting Cinder lvm.conf

We added an lvm filter for use when using Cinder's
LVM driver that would only scan devices that we have
actually deployed Cinder Volume Groups on.

This patch adds a simple output message to the setup
routine so we can more easily inspect what was found
and what has been set during devstack setup.

Change-Id: Iba5012caffd45dfb5143b6df954eed277445a60e
diff --git a/lib/cinder_backends/lvm b/lib/cinder_backends/lvm
index 4b9d8dc..d83c31a 100644
--- a/lib/cinder_backends/lvm
+++ b/lib/cinder_backends/lvm
@@ -77,6 +77,7 @@
     local line
 
     for pv_info in $(sudo pvs --noheadings -o name,vg_name --separator ';'); do
+        echo_summary "Evaluate PV info for Cinder lvm.conf: $pv_info"
         IFS=';' read pv vg <<< $pv_info
         for line in ${conf_entries}; do
             IFS='=' read label group <<< $line