Fix Heka meta to support alternative log location

Depending on which version of the neutron-server package is installed,
the log file may be at /var/log/neutron/server.log or
/var/log/neutron/neutron-server.log. This change supports both options.

Change-Id: If4a86c6ef29948de83d0a86c98d2e62e1db06ceb
diff --git a/neutron/meta/heka.yml b/neutron/meta/heka.yml
index b14c967..1fc60ff 100644
--- a/neutron/meta/heka.yml
+++ b/neutron/meta/heka.yml
@@ -28,7 +28,10 @@
     neutron_log:
       engine: logstreamer
       log_directory: "/var/log"
-      file_match: 'neutron/(?P<Service>(dhcp-agent|l3-agent|metadata-agent|neutron-netns-cleanup|openvswitch-agent|neutron-lbaas-agent|server))\.log\.?(?P<Seq>\d*)$'
+      # Depending on the package version, the Neutron server logs are either at
+      # /var/log/neutron/neutron-server.log or /var/log/neutron/server.log and
+      # the following regexp will deal with both situations.
+      file_match: 'neutron/(neutron-)?(?P<Service>(dhcp-agent|l3-agent|metadata-agent|neutron-netns-cleanup|openvswitch-agent|neutron-lbaas-agent|server))\.log\.?(?P<Seq>\d*)$'
       differentiator: ['neutron', '_', 'Service']
       priority: ["^Seq"]
       decoder: "neutron_decoder"