CA-327302: report signals in CommandException
CA-327302: report signals in CommandException

Negative process exit codes indicate that the process terminated
with a signal so report these separately.

Signed-off-by: Mark Syms <655512b2a8f1aba6e4085462b623575da824f038@citrix.com>

xapi-project/sm,xapi-project/sm,xapi-project/sm