return to -dev version

Change-Id: Ia2cbdaba68e31d3db0be77999b3f397b0270efd9
diff --git a/VERSION b/VERSION
index 21bb5e1..f963933 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.2.5
+2.2.6-dev