[infiniband] Generate more specific errors in response to failure MADs
Generate errors within individual MAD transaction consumers such as
ib_pathrec.c and ib_mcast.c, rather than within ib_mi.c. This allows
for more meaningful error messages to eventually be displayed to the
user.
[infiniband] Add the concept of a management interface
A management interface is the component through which both local and
remote management agents are accessed.
This new implementation of a management interface allows for the user
to react to timed-out transactions, and also allows for cancellation
of in-progress transactions.