PEL: Clear PLDM instance IDs in certain cases
PEL: Clear PLDM instance IDs in certain cases

When the host powers off or the code hits the maximum amount of retries
after a failure and gives up, call the PLDM interface's cancelCmd
function to ensure that the code will get a new instance ID on any
future attempts at sending a PEL to the host.

Note that in the power off case the PLDMInterface class would only have
an instance ID around if it was in the middle of sending a command at
the time.

It is doing this because there is no way to know when the next attempt
at sending up a PEL will occur, it could be months or years, and it
can't assume the PLDM daemon will not have already given that ID to
someone else by then.

Signed-off-by: Matt Spinler <c000c989d08c98662d98f15448f11de169feb92d@us.ibm.com>
Change-Id: I6cd5ef6131ee0b2a205fcf71db5a2bfaa2e44e36

openbmc/phosphor-logging,openbmc/phosphor-logging,openbmc/phosphor-logging,openbmc/phosphor-logging