Set correct default branch in gitreview

Change-Id: Id52830679a45584a33ea7ee8eeec74028e829bb8
diff --git a/.gitreview b/.gitreview
index a080b19..ea5b924 100644
--- a/.gitreview
+++ b/.gitreview
@@ -2,3 +2,4 @@
 host=gerrit.mcp.mirantis.net
 port=29418
 project=salt-models/mcp-virtual-aio
+defaultbranch=stable/mitaka