AppDynamics Node Name Prefix Environment Variable

This change includes adds an environment variable that allows a user to
specify the prefix applied to an AppDynamics Node Name.

[resolves #749]

Signed-off-by: Ben Hale <[email protected]>

Author: jeffaholmes

config/app_dynamics_agent.yml

@@ -18,6 +18,6 @@
 version: 4.+
 repository_root: https://packages.appdynamics.com/java
 default_application_name: $(jq -r -n "$VCAP_APPLICATION | .space_name + \":\" + .application_name | @sh")
-default_node_name: $(jq -r -n "$VCAP_APPLICATION | .application_name + \":$CF_INSTANCE_INDEX\"")
+default_node_name: $(jq -r -n "\"$APPD_CF_NODE_PREFIX\" + ($VCAP_APPLICATION | .application_name) + \":$CF_INSTANCE_INDEX\"")
 default_tier_name: 
 default_unique_host_name: $(jq -r -n "$VCAP_APPLICATION | .application_id + \":$CF_INSTANCE_INDEX\"")