ls-files and read-tree need core.filemode

ls-files.c and read-tree.c miss the default configuration, in
particular the filemode=false part.  The recent +x bit flip made me
notice that, because git-merge refused to merge anything saying that
git-pull.sh is not up to date.

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/ls-files.c b/ls-files.c
index f7653e7..db2288a 100644
--- a/ls-files.c
+++ b/ls-files.c
@@ -570,6 +570,7 @@
 	prefix = setup_git_directory();
 	if (prefix)
 		prefix_offset = strlen(prefix);
+	git_config(git_default_config);
 
 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];
diff --git a/read-tree.c b/read-tree.c
index 6a456ae..df156ea 100644
--- a/read-tree.c
+++ b/read-tree.c
@@ -633,6 +633,8 @@
 	if (newfd < 0)
 		die("unable to create new cachefile");
 
+	git_config(git_default_config);
+
 	merge = 0;
 	reset = 0;
 	for (i = 1; i < argc; i++) {