Switch statsd config to zuul.conf

The automatic statsd configuration based on env variables has
proven cumbersome and counter-intuitive.  Move its configuration
into zuul.conf in preparation for other components emitting stats.

Change-Id: I3f6b5010d31c05e295f3d70925cac8460d334283
diff --git a/tests/fixtures/zuul.conf b/tests/fixtures/zuul.conf
index 7bc8c59..e6f997c 100644
--- a/tests/fixtures/zuul.conf
+++ b/tests/fixtures/zuul.conf
@@ -1,6 +1,11 @@
 [gearman]
 server=127.0.0.1
 
+[statsd]
+# note, use 127.0.0.1 rather than localhost to avoid getting ipv6
+# see: https://github.com/jsocol/pystatsd/issues/61
+server=127.0.0.1
+
 [scheduler]
 tenant_config=main.yaml