Change path to loadbalancer plugin

LoadbalancerPlugin path needs to be changed to reflect renaming
agent_loadbalancer to loadbalancer and moving services directory
one level up.

Change-Id: Ib2ece411b5fb84575673a66421eb474888dd8f43
diff --git a/lib/quantum b/lib/quantum
index 1a826f8..977a835 100644
--- a/lib/quantum
+++ b/lib/quantum
@@ -187,7 +187,7 @@
 # -------------------------------------------
 
 # Hardcoding for 1 service plugin for now
-source $TOP_DIR/lib/quantum_plugins/services/agent_loadbalancer
+source $TOP_DIR/lib/quantum_plugins/services/loadbalancer
 
 # Use security group or not
 if has_quantum_plugin_security_group; then