Fix emit interface added signal

Send the interface added signal once the object is fully
populated.

Here we are fixing this behaviour for two D-bus objects
1) Root Dbus object for user manager app.
2) Individual user D-bus object.

Before this fix was getting two signals for creation of user/manager
signal time=1562577322.850104 sender=:1.57 -> destination=(null destination) serial=346
       path=/xyz/openbmc_project/user; interface=org.freedesktop.DBus.ObjectManager; member=InterfacesAdded
signal time=1562577322.897089 sender=:1.57 -> destination=(null destination) serial=347
       path=/xyz/openbmc_project/user; interface=org.freedesktop.DBus.ObjectManager; member=InterfacesAdded

After the fix was getting single signal
signal time=1562577775.550198 sender=:1.156 -> destination=(null destination) serial=27
       path=/xyz/openbmc_project/user; interface=org.freedesktop.DBus.ObjectManager; member=InterfacesAdded

Change-Id: I20ac168fe4fc7cd94cd2032db6ebc1623af5943d
Signed-off-by: Ratan Gupta <ratagupt@linux.vnet.ibm.com>
4 files changed