fix service differentiator

Change-Id: I535895f8bc98f18d041cf0f37a000c013c488f8b
diff --git a/glance/files/heka.toml b/glance/files/heka.toml
index abae8fd..8affda6 100644
--- a/glance/files/heka.toml
+++ b/glance/files/heka.toml
@@ -3,7 +3,7 @@
 type = "LogstreamerInput"
 log_directory = "/var/log/glance"
 file_match = '(?P<Service>.+)\.log\.?(?P<Seq>\d*)$'
-differentiator = ["'glance','_','Service'"]
+differentiator = ['glance','_','Service']
 priority = ["^Index"]
 decoder = "openstack"