Support installing os-traits from git

This will be used in a src job for running os-traits changes
in a dsvm/tempest setup.

Change-Id: I3c4433fb1ca2787e96b577a15d584b625c364ef3
diff --git a/stackrc b/stackrc
index e9b8df2..6d11589 100644
--- a/stackrc
+++ b/stackrc
@@ -570,6 +570,10 @@
 GITBRANCH["neutron-lib"]=${NEUTRON_LIB_BRANCH:-master}
 GITDIR["neutron-lib"]=$DEST/neutron-lib
 
+# os-traits library for resource provider traits in the placement service
+GITREPO["os-traits"]=${OS_TRAITS_REPO:-${GIT_BASE}/openstack/os-traits.git}
+GITBRANCH["os-traits"]=${OS_TRAITS_BRANCH:-master}
+
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 #  TripleO / Heat Agent Components