libafs: Put back GetCapabilities user reference

libafs: Put back GetCapabilities user reference

afs_GetCapabilities gets a user reference for the conn for the
GetCapabilities call. Put the ref back so we don't leak refs.

Reviewed-on: http://gerrit.openafs.org/4626
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit 010fc998a51a0aae2499b128ee8c671885a84e13)

Change-Id: Ia505de8e5ec7ded14f2e2e40ac8bd3ef0b91c2fc
Reviewed-on: http://gerrit.openafs.org/4637
Tested-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@dementia.org>