dlm: Delete an error message for a failed memory allocation in dlm_recover_waiters_pre()

Omit an extra message for a memory allocation failure in this function.

Link: http://events.linuxfoundation.org/sites/events/files/slides/LCJ16-Refactor_Strings-WSang_0.pdf


Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: David Teigland <teigland@redhat.com>