Move all of the error prints in readsb() from stderr to stdout.

The only output from fsck that should go to stderr is the usage message.
if setup() fails then exit with EEXIT rather than 0.

Reviewed by:	mckusick
Sponsored by:	Netflix

sbin/fsck_ffs/main.c

@@ -408,7 +408,7 @@ checkfilesys(char *filesys)
 	case 0:
 		if (preen)
 			pfatal("CAN'T CHECK FILE SYSTEM.");
-		return (0);
+		return (EEXIT);
 	case -1:
 	clean:
 		pwarn("clean, %ld free ", (long)(sblock.fs_cstotal.cs_nffree +

sbin/fsck_ffs/setup.c

@@ -339,15 +339,15 @@ readsb(int listerr)
 			return (0);
 		case ENOENT:
 			if (bflag)
-				fprintf(stderr, "%jd is not a file system "
+				printf("%jd is not a file system "
 				    "superblock\n", super / dev_bsize);
 			else
-				fprintf(stderr, "Cannot find file system "
+				printf("Cannot find file system "
 				    "superblock\n");
 			return (0);
 		case EIO:
 		default:
-			fprintf(stderr, "I/O error reading %jd\n",
+			printf("I/O error reading %jd\n",
 			    super / dev_bsize);
 			return (0);
 		}