sensor:monitor: Use a single PowerState object

Now that both monitor classes need to know about power state, change
them to keep a shared_ptr to a PowerState object and then pass the
object into their constructors.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: Ia83217e8af51204bbb3fc6e8e3f2eac5912b5913
5 files changed