Windows: remove unused label in ntops.c

Windows: remove unused label in ntops.c

The label 'retry' in nt_open is not used and was causing a warning.  Remove it.

Reviewed-on: http://gerrit.openafs.org/3747
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
(cherry picked from commit 40497fa667d15aaaa8f6befdc45cff40cc544616)

Change-Id: I7887e4ba31556b2bf6b1e2a4867aecd1e8b41297
Reviewed-on: http://gerrit.openafs.org/3860
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>