[VOL-5257] Release patch repo:voltha-onos (branch=voltha-2.12)

VERSION
.gitreview
----------
 o Post release tag & branch patch for branch=voltha-2.12.
 o Bump version string to avoid conflicts:
   - branch=master  (X.{1+Y}.0)
   - branch=release (X.Y.{1+Z})
 o Update .gitreview (defaultpath=voltha-2.12), specify rebase/merge target.

Change-Id: I3d3d37ba9fc381f2ff0d1ba510a63ae59f767cd0
diff --git a/.gitreview b/.gitreview
index 473a40c..dbac480 100644
--- a/.gitreview
+++ b/.gitreview
@@ -3,4 +3,4 @@
 port=29418
 project=voltha-onos.git
 defaultremote=origin
-defaultbranch=master
+defaultbranch=voltha-2.12
diff --git a/VERSION b/VERSION
index fc3aa77..48ea19b 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-5.1.9
+5.1.10