mktag: use default strbuf_read() hint

Change the hardcoded hint of 2^12 to 0. The default strbuf hint is
perfectly fine here, and the only reason we were hardcoding it is
because it survived migration from a pre-strbuf fixed-sized buffer.

See fd17f5b (Replace all read_fd use with strbuf_read, and get rid
of it., 2007-09-10) for that migration.

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

builtin/mktag.c

@@ -161,7 +161,7 @@ int cmd_mktag(int argc, const char **argv, const char *prefix)
 	if (argc != 1)
 		usage("git mktag");
 
-	if (strbuf_read(&buf, 0, 4096) < 0) {
+	if (strbuf_read(&buf, 0, 0) < 0) {
 		die_errno("could not read from stdin");
 	}