bos: Don't set up the conenction twice in AddKey

AddKey calls GetConn twice - once at the start of the function,
and then again immediately before calling BOZO_AddKey. This leaks
a connection...

Caught by clang-analyzer

Reviewed-on: http://gerrit.openafs.org/9230
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
(cherry picked from commit 6ef224da14da88318ede836a2c80998299c93e2f)

Change-Id: I6cbd68a72b041a9638d98481ef793e34b8946abd
Reviewed-on: http://gerrit.openafs.org/10859
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Perry Ruiter <pruiter@sinenomine.net>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>