httpd: emit correct content length on range requests past the end. Closes 4952

Signed-off-by: Rob Walker <rwalker@codeaurora.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/httpd.c b/networking/httpd.c
index f233cb0..fb6ecbf 100644
--- a/networking/httpd.c
+++ b/networking/httpd.c
@@ -1594,7 +1594,7 @@
 	}
 	range_len = MAXINT(off_t);
 	if (range_start >= 0) {
-		if (!range_end) {
+		if (!range_end || range_end > file_size - 1) {
 			range_end = file_size - 1;
 		}
 		if (range_end < range_start