Improve error message when mode is set twice.

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>

ChangeLog

@@ -15,8 +15,7 @@ Changes Prior to 1.9.0 release
 	it to find devices, rather than only once.
     -   Make "mdadm -Ss" stop stacked devices properly, by reversing the
 	order in which arrays are stopped.
-    -   Correct error message when last device to be added to an array
-        fails.
+    -   Improve some error messages.
 
 Changes Prior to 1.8.0 release
     -   Makefile cleanup from  Luca Berra <bluca@comedia.it>

mdadm.c

@@ -172,7 +172,7 @@ int main(int argc, char *argv[])
 				fprintf(stderr, "--%s", long_options[option_index].name);
 			else
 				fprintf(stderr, "-%c", opt);
-			fprintf(stderr, " would set mode to %s, but it is already %s.\n",
+			fprintf(stderr, " would set mdadm mode to \"%s\", but it is already set to \"%s\".\n",
 				map_num(modes, newmode),
 				map_num(modes, mode));
 			exit(2);