Post release: bump version string for development

Change-Id: I5047e681f4a72327e56911a1fcb45ef603b8cb0f
diff --git a/VERSION b/VERSION
index 2c9b4ef..2d6d89e 100755
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.7.3
+2.7.4-dev