diff: demote core.safecrlf=true to core.safecrlf=warn

Otherwise the user will not be able to start to guess where in the
contents in the working tree the offending unsafe CR lies.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/diff.c b/diff.c
index 32142db..3e406f1 100644
--- a/diff.c
+++ b/diff.c
@@ -2647,6 +2647,14 @@
 int diff_populate_filespec(struct diff_filespec *s, int size_only)
 {
 	int err = 0;
+	/*
+	 * demote FAIL to WARN to allow inspecting the situation
+	 * instead of refusing.
+	 */
+	enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
+				    ? SAFE_CRLF_WARN
+				    : safe_crlf);
+
 	if (!DIFF_FILE_VALID(s))
 		die("internal error: asking to populate invalid file.");
 	if (S_ISDIR(s->mode))
@@ -2702,7 +2710,7 @@
 		/*
 		 * Convert from working tree format to canonical git format
 		 */
-		if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
+		if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
 			size_t size = 0;
 			munmap(s->data, s->size);
 			s->should_munmap = 0;