LU-10903 obdecho: use OBD_ALLOC_LARGE for lnb

LU-10903 obdecho: use OBD_ALLOC_LARGE for lnb

When allocating the niobuf_local, if there are a large number of
(potential) fragments this allocation can be quite large.  Use
OBD_ALLOC_LARGE(lnb) and OBD_FREE_LARGE(lnb) to avoid allocation
errors and console noise.  This was causing sanity test_180c to
fail in a VM on occasion, and could also be problem in real use.

Tidy up test_180[abc] to use stack_trap to handle echo device
cleanup rather than having a series of conditional checks.
Use "error" to report errors rather than error numbers.

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: Ib0e721f58fc0a62acca29b31fb4dfac5021cab07
Reviewed-on: https://review.whamcloud.com/31964
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Emoly Liu <emoly.liu@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>