join(1): Fix field ordering for -v output

Per POSIX, join(1) (in modes other than -o) is a concatenation of selected
character fields.  The joined field is first, followed by fields in the
order they occurred in the input files.

Our join(1) utility previously handled this correctly for lines with a match
in the other file.  But it failed to order output fields correctly for
unmatched lines, printed in -a and -v modes.

A simple test case is:

$ touch a
$ echo "2 1" > b
$ join -v2 -2 2 a b
1 2

PR:		217711
Reported by:	alt.j2-4o4s2yon at yopmail.com
Sponsored by:	Dell EMC Isilon

1 files changed, 8 insertions, 2 deletions

diff --git a/usr.bin/join/join.c b/usr.bin/join/join.c
index 0e66338a80a85..f7906a931f21c 100644
--- a/usr.bin/join/join.c
+++ b/usr.bin/join/join.c
@@ -467,9 +467,15 @@ outoneline(INPUT *F, LINE *lp)
 			else
 				outfield(lp, 0, 1);
 		}
-	else
+	else {
+		/*
+		 * Output the join field, then the remaining fields.
+		 */
+		outfield(lp, F->joinf, 0);
 		for (cnt = 0; cnt < lp->fieldcnt; ++cnt)
-			outfield(lp, cnt, 0);
+			if (F->joinf != cnt)
+				outfield(lp, cnt, 0);
+	}
 	(void)printf("\n");
 	if (ferror(stdout))
 		err(1, "stdout");