The default rpi completion handler does back to back puts to force the
removal of the ndlp. This ends up calling lpfc_unreg_rpi after the
reference count is at 0.

Fix:  Check the reference count of the ndlp before getting the ref to
make sure we are not getting a reference on a removed object.
Signed-off-by: NDick Kennedy <dick.kennedy@avagotech.com>
Signed-off-by: NJames Smart <james.smart@avagotech.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>