diff-lib.c: remove the_repository references

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/commit.c b/builtin/commit.c
index e89bf35..91b1920 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -908,7 +908,8 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 			if (ignore_submodule_arg &&
 			    !strcmp(ignore_submodule_arg, "all"))
 				flags.ignore_submodules = 1;
-			committable = index_differs_from(parent, &flags, 1);
+			committable = index_differs_from(the_repository,
+							 parent, &flags, 1);
 		}
 	}
 	strbuf_release(&committer_ident);