docs: Belatedly update for move of qmp-commands.txt

Missed in commit d076a2a and commit bd6092e.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1474546563-16332-1-git-send-email-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

docs/xen-save-devices-state.txt

@@ -9,7 +9,7 @@ however it is also possible to save the state of all devices to file,
 without saving the RAM or the block devices of the VM.
 
 This operation is called "xen-save-devices-state" (see
-QMP/qmp-commands.txt)
+qmp-commands.txt)
 
 
 The binary format used in the file is the following: