LU-10973 lnet: initialize buffers properly

LU-10973 lnet: initialize buffers properly

Initialize the error message buffer properly to avoid
garbage characters printed out.

Test-Parameters: trivial
Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I9c0d08ea2baf0cda990e3abb7e7de497a5226bfe
Reviewed-on: https://review.whamcloud.com/38083
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>