fix lowercase for disable_flow_collection for vrouter

Change-Id: Ife859ff284501bdf0b93ddc992a7e87c4c1fe991
diff --git a/opencontrail/files/2.2/contrail-vrouter-agent.conf b/opencontrail/files/2.2/contrail-vrouter-agent.conf
index 3b6e9af..b33d034 100644
--- a/opencontrail/files/2.2/contrail-vrouter-agent.conf
+++ b/opencontrail/files/2.2/contrail-vrouter-agent.conf
@@ -51,7 +51,7 @@
 
 # Disable sending of flow samples to collector. Possible values are 0 and 1
 # disable_flow_collection=false
-disable_flow_collection={{ compute.get('disable_flow_collection', 'false') }}
+disable_flow_collection={{ compute.get('disable_flow_collection', 'false')|lower }}
 
 # Encapsulation type for tunnel. Possible values are MPLSoGRE, MPLSoUDP, VXLAN
 # tunnel_type=