Add missing break statement so e2fsck -k actually works.  
(Addresses Debian Bug #234993)

diff --git a/e2fsck/unix.c b/e2fsck/unix.c
index 55dcfc1..89c2fa6 100644
--- a/e2fsck/unix.c
+++ b/e2fsck/unix.c
@@ -678,6 +678,7 @@
 #endif
 		case 'k':
 			keep_bad_blocks++;
+			break;
 		default:
 			usage(ctx);
 		}