LU-4423 lnet: free a struct kib_conn outside of the kiblnd_destroy_conn()

To avoid confusion this fix moved the freeing a struct kib_conn outside of
the function kiblnd_destroy_conn().

Change-Id: Iae28802f5d319570064a504feb14dffd13a22b84
Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-on: https://review.whamcloud.com/31273


Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Sonia Sharma <sonia.sharma@intel.com>
Reviewed-by: Doug Oucharek <dougso@me.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>