LU-346 fix conf-sanity test_23a

LU-346 fix conf-sanity test_23a

ctrl-c sends SIGINT signal, and the SIGINT will be delivered to the
process tree, but it does not work on non-job-controlled (usually in
script) child process.

SIGTERM works on child process, but it does not spread offspring
processes, so we send it to all lustre mount processes.

excerpt from bash manpage:

set [--abefhkmnptuvxBCEHPT] [-o option-name] [arg ...]
set [+abefhkmnptuvxBCEHPT] [+o option-name] [arg ...]
 -m      Monitor mode. Job control is enabled. This option is on by
         default for interactive shells on systems that support it.
Non-builtin  commands run by bash have signal handlers set to the
values inherited by the shell from its parent.  When job control is
not in effect, asynchronous commands ignore SIGINT and SIGQUIT in
addition to these inherited handlers.

Change-Id: I099fe53373470ad2182f7bd20ff88cb896b1f955
Signed-off-by: Bobi Jam <bobijam@whamcloud.com>
Reviewed-on: http://review.whamcloud.com/1049
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>