sh: Fix signal messages being sent to the wrong file sometimes.

When a foreground job exits on a signal, a message is printed to stdout
about this. The buffer was not flushed after this which could result in the
message being written to the wrong file if the next command was a builtin
and had stdout redirected.

Example:
  sh -c 'kill -9 $$'; : > foo; echo FOO:; cat foo

Reported by:	gcooper
MFC after:	1 week

1 files changed, 1 insertions, 0 deletions

diff --git a/bin/sh/jobs.c b/bin/sh/jobs.c
index fda167b..ea8c8f8 100644
--- a/bin/sh/jobs.c
+++ b/bin/sh/jobs.c
@@ -1062,6 +1062,7 @@ dowait(int block, struct job *job)
 			if (coredump)
 				out1str(" (core dumped)");
 			out1c('\n');
+			flushout(out1);
 		}
 	} else {
 		TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));