remove a left-over break

By the "same logic as above...", we want to continue to fallback here,
but the break prohibits that.

This is a follow-up for ee1aa61c47 .

src/shared/copy.c

@@ -244,7 +244,6 @@ int copy_bytes_full(
                                         break;
 
                                 try_sendfile = try_splice = false; /* same logic as above for copy_file_range() */
-                                break;
                         } else
                                 /* Success! */
                                 goto next;