afs: Translate VNOSERVICE to ETIMEDOUT

Some fileservers will kill calls that are taking too long with the
VNOSERVICE abort code. Our logic for retrying calls is already aware
of this usage, but if we cannot retry the call, we still just return
VNOSERVICE as an error code to our caller.

Don't return this raw, since has the same value as ENOBUFS, which can
cause a confusing error message from logs or applications ("No buffer
space available"). Return ETIMEDOUT instead.

Reviewed-on: http://gerrit.openafs.org/10766
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: Andrew Deason <adeason@sinenomine.net>
(cherry picked from commit 335a70653adb59795f262663af3972de016c068d)

Change-Id: Ia0b4dbfb61353c08917898c3cb9128625023f311
Reviewed-on: http://gerrit.openafs.org/10814
Reviewed-by: Perry Ruiter <pruiter@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: D Brashear <shadow@your-file-system.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>