rainier: Add dbus-sensors

Add dbus-sensors to the Rainier flash image.  This repository holds a
suite of applications for managing various types of sensors.  It uses
D-Bus interfaces provided by entity-manager to know which sensors to
monitor.  Rainier will use it for at least some of the temperature
sensors.

(From meta-ibm rev: 29cc525d9cb736f4cfa0bc17bb45771fd812234e)

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I81f9311adb9d72de1b04f9aed0a2d9e778b3e03a
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>