fate.txt: replace FATE rsync command with a make command

Remove reference to the mplayerhq.hu rsync command, and replace it
with a reference to the make fate-rsync command.

rsync needs still to be enabled on mplayerhq.hu, and it is currently
not working. Also the fate-rsync Makefile target can be easily updated
without the need to keep the docs in synch.

doc/fate.txt

@@ -7,8 +7,7 @@ that is provided separately from the actual source distribution.
 
 Use the following command to get the fate test samples
 
-# rsync -aL rsync://rsync.mplayerhq.hu:/samples/fate-suite/ fate/fate-suite
-# rsync -aL rsync://fate-suite.libav.org:/fate-suite/ fate-suite
+# make fate-rsync SAMPLES=fate-suite/
 
 To inform the build system about the testsuite location, pass
 `--samples=<path to the samples>` to configure or set the SAMPLES Make