add dbus_service name for different platforms

on redhat6.4/centos, the dbus_service name is
messagebus, and on other platforms, it's dbus.
So I enhanced it, and updated the CHANGELOG.md
and metadata.rb .

Change-Id: I5548acc38b5e2cbf5e1d5d482cadbd876392daa4
Closes-Bug: #1244574
Merge "add dbus_service name for different platforms"