Until now, the Linux-USB core has always chosen the first device
configuration, even when there was a choice.  In 2.4 kernels,
device driver probe() routines were allowed to override that
initial policy decisions.  But 2.6 kernels can't do that from
probe() routines, causing problems with some CDC-ACM modems
where the first config uses MSFT-proprietary protocols.

This patch switches to a smarter heuristic:  Linux now prefers
standard interface classes when there's a choice.  So those
CDC-ACM modems don't need a "write bConfigurationValue in sysfs"
step when they are connected; they act just like on 2.4 kernels.
(And sysfs can still be used to handle any problem cases.)