Move keystore to Android.bp.

Test: builds, boots
Bug: 67041047
Change-Id: I4ec9ddc69552d853e7d1c2296dcd8de8cb3f5942
diff --git a/Android.bp b/Android.bp
new file mode 100644
index 0000000..b44c296
--- /dev/null
+++ b/Android.bp
@@ -0,0 +1 @@
+subdirs = ["*"]