Require gear 0.3.1.

And less than 0.4.0 for safety.

Change-Id: I539a2cc7816c15491db55975ac07ee7a148535dc
Reviewed-on: https://review.openstack.org/32973
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins
diff --git a/tools/pip-requires b/tools/pip-requires
index 06207aa..4bd98ff 100644
--- a/tools/pip-requires
+++ b/tools/pip-requires
@@ -9,4 +9,4 @@
 extras
 statsd>=1.0.0,<3.0
 voluptuous>=0.6,<0.7
-gear>=0.2.0,<1.0
+gear>=0.3.1,<0.4.0