Fix a spelling misstake.

Reference: /n/sources/patch/applied/nedmail-typo
Date: Sun Oct  7 21:12:18 CES 2007
Signed-off-by: miller@hamnavoe.com

--- /sys/src/cmd/upas/ned/nedmail.c	Sun Oct  7 21:11:13 2007
+++ /sys/src/cmd/upas/ned/nedmail.c	Sun Oct  7 21:11:07 2007
@@ -1308,7 +1308,7 @@
 	fd = open(s_to_c(path), OREAD);
 	s_free(path);
 	if(fd < 0){
-		fprint(2, "!message dissappeared\n");
+		fprint(2, "!message disappeared\n");
 		return 0;
 	}
 	tot = 0;
@@ -1453,7 +1453,7 @@
 	b = Bopen(s_to_c(path), OREAD);
 	s_free(path);
 	if(b == nil){
-		fprint(2, "!message dissappeared\n");
+		fprint(2, "!message disappeared\n");
 		return;
 	}
 	while((p = Brdline(b, '\n')) != nil){