Turn replaygain application off when impossible

Addition to commit 808efb3. That commit threw a warning, but did
not actually turn off replaygain application.

Credit: Oss-Fuzz
Issue: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=70482

src/flac/decode.c

@@ -1590,6 +1590,7 @@ void metadata_callback(const FLAC__StreamDecoder *decoder, const FLAC__StreamMet
 					decoder_session->abort_flag = true;
 					return;
 				}
+				decoder_session->replaygain.apply = false;
 			}
 			else {
 				const char *ls[] = { "no", "peak", "hard" };