aoe: remove vestigial request queue allocation

aoe: remove vestigial request queue allocation

Before the aoe driver was an I/O request handler, it was a
make_request-style block driver.  Even so, there was a problem where sysfs
expected a request queue to exist, so one was provided in commit
7135a71b19be1fa ("aoe: allocate unused request_queue for sysfs").

During the transition to the request-handler style, a patch was merged
that was based on a driver without the noop queue, and the noop queue
remained in place after the patch was merged, even though a new functional
queue was introduced by the patch, allocated through blk_init_queue.

The user impact is a memory leak proportional to the number of AoE targets
discovered.  This patch removes the memory leak and cleans up vestiges of
the old do-nothing queue from the aoeblk_gdalloc function.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>