Tests: adjusted mp4 test for end value beyond track duration.

mp4.t

diff --git a/mp4.t b/mp4.t
index 7d72822..288500d 100644
--- a/mp4.t
+++ b/mp4.t
@@ -77,9 +77,10 @@
 like(http_head('/test.mp4?start=1&end=1'), qr/200 OK/, 'zero range');
 like(http_head('/test.mp4?start=1&end=0'), qr/200 OK/, 'negative range');
 
-# start/end values exceeding file duration
+# start/end values exceeding track/file duration
 
-like(http_head("/test.mp4?end=11"), qr!HTTP/1.1 500!, 'end beyond EOF');
+unlike(http_head("/test.mp4?end=11"), qr!HTTP/1.1 500!,
+	'end beyond short track');
 
 }