Fix unreachable error

core/os/os_openbsd.odin

@@ -577,7 +577,6 @@ _readlink :: proc(path: string) -> (string, Errno) {
 			return strings.string_from_ptr(&buf[0], rc), ERROR_NONE
 		}	
 	}
-	unreachable()
 }
 
 // XXX OpenBSD