clone/sha1_file: read info/alternates with strbuf_getline()

$GIT_OBJECT_DIRECTORY/info/alternates is a text file that can be
edited with a DOS editor.  We do not want to use the real path with
CR appended at the end.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/clone.c b/builtin/clone.c
index 29741f4..43b4c99 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -339,7 +339,7 @@
 	FILE *in = fopen(src->buf, "r");
 	struct strbuf line = STRBUF_INIT;
 
-	while (strbuf_getline_lf(&line, in) != EOF) {
+	while (strbuf_getline(&line, in) != EOF) {
 		char *abs_path;
 		if (!line.len || line.buf[0] == '#')
 			continue;