Enforce consistent formatting of .bp files

Test: attempt to checking in badly formatted .bp file
Change-Id: Ibd8662a55b86bc3ff8d69af71fae4a0b54359009
diff --git a/PREUPLOAD.cfg b/PREUPLOAD.cfg
new file mode 100644
index 0000000..321bab6
--- /dev/null
+++ b/PREUPLOAD.cfg
@@ -0,0 +1,2 @@
+[Builtin Hooks]
+bpfmt = true