sensor-monitor: Capture PID in event logs

Pass the PID of the process into an event log with the _PID additional
data entry.  This gets done automatically when the report() or commit()
phosphor-logging event log library functions are called, but needs to be
done manually when the D-Bus API is used.  This just provides a way to
see which process created the event log and I just forgot to do this
when I first wrote it..

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I094a0eb9634df53759f257799ae518ffd63e45cd
2 files changed