fix service differentiator

Change-Id: I8d95909b8152b50c74c4f60ce303077251a53f6c
diff --git a/cinder/files/heka.toml b/cinder/files/heka.toml
index 4ca7346..7a200bb 100644
--- a/cinder/files/heka.toml
+++ b/cinder/files/heka.toml
@@ -2,7 +2,7 @@
 type = "LogstreamerInput"
 log_directory = "/var/log/cinder"
 file_match = '(?P<Service>.+)\.log\.?(?P<Seq>\d*)$'
-differentiator = ["'cinder','_','Service'"]
+differentiator = ['cinder','_','Service']
 priority = ["^Index"]
 decoder = "openstack"