Add permission checking for binder IPC. Thanks Stephen Smalley
Do not apply permission checks to private files.

Change-Id: I472d9630de5113667c289dce7e4fdc8eace04e36
Fix security_binder_transfer_binder hook.

Drop the owning task argument to security_binder_transfer_binder
since ref->node->proc can be NULL (dead owner?).
Revise the SELinux checking to apply a single transfer check between
the source and destination tasks.  Owning task is no longer relevant.
Drop the receive permission definition as it is no longer used.

This makes the transfer permission similar to the call permission; it is only
useful if you want to allow a binder IPC between two tasks (call permission)
but deny passing of binder references between them (transfer permission).

Change-Id: I6ec460ede8e07dadc9f52b61534b2b0021617302
Do not ratelimit audit messages. We want to see them all.

Change-Id: I19c29788cc33b0f59e0bdfe04fe67c247239c559
Update .gitignore