Revert 169164 - Allow multiple object proxies to handle NameOwnerChanged

Revert 169164 - Allow multiple object proxies to handle NameOwnerChanged

Failed on Linux ChromiumOS Tests:

SignalSenderVerificationTest.TestMultipleObjects: 
[4218:4244:1121/160846:447516037:ERROR:object_proxy.cc(624)] Failed to get name owner. Got org.freedesktop.DBus.Error.NameHasNoOwner: Could not get owner of name 'org.chromium.TestService': no such name
[4218:4244:1121/160846:447531010:ERROR:bus.cc(444)] Failed to get the ownership of org.chromium.TestService:
[4218:4248:1121/160846:447531228:ERROR:test_service.cc(134)] Failed to own: org.chromium.TestService
dbus/signal_sender_verification_unittest.cc:302: Failure
Value of: on_name_owner_changed_called_
Actual: false
Expected: true
[4218:4244:1121/160846:447535382:ERROR:bus.cc(604)] Requested to remove an unknown match rule: type='signal',interface='org.freedesktop.DBus',member='NameOwnerChanged',path='/org/freedesktop/DBus',sender='org.freedesktop.DBus',arg0='org.chromium.TestService'

http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%28dbg%29%281%29/builds/12886/steps/dbus_unittests/logs/TestMultipleObjects

Multiple object proxies may be registered for any single D-Bus service, one per interface. Returning "handled" means only the first interface object proxy gets to handle the signal, others never see it.

Change to always return "not yet handled", while this means D-Bus never knows we actually handled the NameOwnerChanged signal, that's quite ok and is actually what all other bindings do for all signals.

BUG=chromium-os:36486
TEST=dbus_unittests

Review URL: https://chromiumcodereview.appspot.com/11280073

TBR=keybuk@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=169170