Fix BUILDING.md document. Remove reference to make 'prereq' target which does not exist anymore.

Change-Id: I1d9c6902636b8188ed420e144470a671adf2f356
diff --git a/VERSION b/VERSION
index 4a36342..05d78bc 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-3.0.0
+3.0.1-dev