Rename Blueprints to Android.bp

Rename module definition files to Android.bp to avoid conflicts
with another project called Blueprint.

Change-Id: I105a07555eb7890f56120deab9036cf9ae5d8525
diff --git a/root.bp b/root.bp
index c8a3ce2..ea17db3 100644
--- a/root.bp
+++ b/root.bp
@@ -1,3 +1,5 @@
+subname = "Android.bp"
+
 subdirs = [
     "art",
     "build/blueprint",