names: clear e->activator when activator has disconnected

As reported by Radoslaw Pajak.

On 02/24/2014 09:39 AM, Radoslaw Pajak wrote:
> If e->activator wasn't released when activator connection has
> disconnected, there was no possibility to open new activator
> connection for that name in the case when there was another
> owner of that name.
Revert "names: clear e->activator when activator has disconnected"

This reverts commit caefc83318261b91ce9f0077eafe4220e0db500f.
FW: [PATCH] names: clear e->activator when activator has disconnected

If e->activator wasn't released when activator connection has disconnected,
there was no possibility to open new activator connection for that name
in the case when there was another owner of that name.

Signed-off-by: Radoslaw Pajak <r.pajak@samsung.com>
names: return -EINVAL if an activator tries to request a second name
names: fix regressions in kdbus_name_remove_by_conn

1. unref the activator connection without the locks held, so we don't
run into ABBA locking situations.

2. dereference conn->activator_of before freeing all the name entry
items.
names: fix return codes and conditions

The conn->names is decreased once the implementor takes over a name from
the activator. Hence, we can't rely on it to check whether a connection
already is the holder of an activatable name.

Refactor the code so that the error codes match:

-EALREADY is returned when the connection already is the owner of the
name is has request to become (activator or implementor)

-EINVAL is returned if the connection is an activator but already owns
a different name entry
test: remove debug left-over
policy: factor out logic to free an item
bus: document kdbus_bus_uid_is_privileged()
connection: cosmetic cleanup
fix kerneldoc
metadata: use the subjective cred of current

In kdbus_meta_append_*() we want to get the subjective context, so
instead of using __task_cred() which reference the objective cred,
use current_cred() to access the subjective cred.

Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
add message queue quota for individual users
domain: user - store the user's index
fix message queue quota logic