If connectivity is lost in the midst of an interrogation,
relay the unreachable status to the client rather than
'Internal Error' that was occuring before.
If a session was attempted but failed before creation, a trace was thrown.
Fix this by catching the scenario and passing, since the desired effect is
already there.
A plugin is now allowed to define a collection. The sensors
hierarchy is added as the first path to allow plugin curated
collections. ipmi plugin updated to list items in those
collections
For exploring the api, a write-only attribute presents difficulty. Address this by allowing
plugins to return a '' value and have ipmi plugin return that value to enable things
like the web api explorer.
Plugins may implement bootmode as appropriate. Currently, the only
example usage is how IPMI can indicate BIOS style versus UEFI style
boot.
Additionally, limitations of the ChoiceMessage base object around
handling multi-parameter pieces of data are addressed.
If there is a persistent IPMI session and the first to notice was a user request
it would fail with unexpected error. Correct the situation to expect the error
and report more precisely as to the cause.
