bin_xtr_dyldcache: Missing R_FREE in a fail path (radareorg#7200)

Author: mikaoP

libr/bin/p/bin_xtr_dyldcache.c

@@ -94,6 +94,7 @@ static RBinXtrData *extract(RBin *bin, int idx) {
 		hdr = MACH0_(get_hdr_from_bytes) (lib->b);
 		if (!hdr) {
 			free (lib);
+			R_FREE (metadata);
 			free (hdr);
 			return NULL;
 		}