LU-9183 libcfs: handle dump_trace() and related callbacks removal

LU-9183 libcfs: handle dump_trace() and related callbacks removal

In commit c8fe4609827aedc9c4b45de80e7cdc8ccfa8541b all previous users
of dump_trace() have been converted to use the new unwind interfaces,
so the dump_trace() and the related print_context_stack() and
print_context_stack_bp() callback functions were removed.

Test-Parameters: trivial
Change-Id: Ifa7a112d622b23f733d6daab05f9838afdf31a86
Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-on: https://review.whamcloud.com/25816
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>