VOL-2030 Return to -dev version

Change-Id: I3ffdd6984db435b1c2436e5870a396a64b567e13
diff --git a/VERSION b/VERSION
index ccbccc3..84e6d84 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.2.0
+2.2.1-dev