fetch: use lstat to verify filesize on existing targets

since we dont verify the checksum we dont need to calculate it
Speed up when you try fetch lots of stuff thats already there.

src/fetch.c

@@ -61,14 +61,13 @@ static int fetch_package(struct fetch_ctx *fctx,
 	int i, r, fd;
 
 	if (!(fctx->flags & FETCH_STDOUT)) {
-		struct apk_file_info fi;
+		struct stat st;
 
 		snprintf(outfile, sizeof(outfile), "%s/%s-%s.apk",
 			 fctx->outdir ? fctx->outdir : ".",
 			 pkg->name->name, pkg->version);
 
-		if (apk_file_get_info(outfile, &fi) == 0 &&
-		    fi.size == pkg->size)
+		if (lstat(outfile, &st) == 0 && st.st_size == pkg->size)
 			return 0;
 	}
 	apk_message("Downloading %s-%s", pkg->name->name, pkg->version);