Windows: more exports afsauthent.dll

Windows: more exports afsauthent.dll

pr_SIdToName
afsconf_GetExtendedCellInfo
afsconf_UpToDate

required for new Explorer Shell functionality

(cherry picked from commit f60bca943f7bc6352a5f7beedbb7ca47559f3513)
Reviewed-on: http://gerrit.openafs.org/3739
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Stefan Kueng <tortoisesvn@gmail.com>
Tested-by: Stefan Kueng <tortoisesvn@gmail.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Change-Id: I0363885c915a9c97bb6f290b5a16d184b244b0b3
Reviewed-on: http://gerrit.openafs.org/3858
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>