Bumping VERSION to 4.2.0-dev

Change-Id: I0b301816273003e509671fd5ac947e458ce25b94
diff --git a/VERSION b/VERSION
index b1cbc1f..5fb11aa 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-4.1.5
+4.2.0-dev