signond: pass the client PID to SignOnUI

This can be useful under the Mir display server, where single-window
apps are referred to by PID.
Merge from upstream

signond: pass the client PID to SignOnUI
Sync from upstream

Pass client PID to SignOn UI. 
Approved by: PS Jenkins bot, David Barth
Releasing 8.57+14.10.20141006-0ubuntu1
signond: pass client AppId to SignOnUi
signond: fix typo
signond: don't bypass the ACL if the identity has no owner
Merge from upstream
signond: on identity update, don't reset missing fields

When Identtity::store() is being called on an existing identity, do not
touch the fields which are not present in the new dictionary of identity
info. Before this commit, all fields which were not present in the new
identity data would be reset to their default value.
Tests: set ACL on new identities

Explicitly set the ACL to "*" on new identities.
Slightly refactor a couple of unit tests.
Tests: add tst_access_control_manager_helper
Test fixes
Tests: fix tst_access_control_manager_helper

The .cpp file was being included by mistake.
Fix tests build
Merge from upstream

Do not bypass the ACL checks if the Identity has no owner. Fixes: #1378660, #1392380
Approved by: PS Jenkins bot, David Barth
Releasing 8.57+15.04.20141127.1-0ubuntu1