sensor-mon: Create event logs

Fill in the function to create event logs.  It creates a different log
for an alarm set versus an alarm clear.

The code will not create event logs for sensors of type 'utilization'
because the application that provides CPU and memory utilization
thresholds hardcodes the threshold values and high CPU usage is expected
in some cases, like during a code update.  If someone does want these
event logs from those alarms then that can be fixed up in the future.

There is also a FRU callout added for the sensor's FRU.  This is done by
following an association, either 'inventory' or 'chassis', depending on
what application provided the sensor.  While the sensor documentation
states that the 'inventory' association would be used to point to the
FRU, nothing in the dbus-sensors code does that and frankly trying to
make that happen isn't worth the effort at this point since it can work
how it is now.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I5689cb47250def28aa2b087f8b1975f5464eb98f
2 files changed