Video player actions sensitive when playback initialization fails

[val461]

I only report this because an error message invited me to, the bug is not annoying to me.
Here is how I can make it happen:

1. GStreamer Libav plug-in must not be installed.
2. Load a .srt file.
3. Load a video for which gaupol requires the above plug-in. A message appears saying that a GStreamer plug-in is missing (“Failed to initialize playback”).
4. Select subtitles and press O (or select Video > Play Selection in the menu bar). An error message appears with the following information:

Traceback

File: /usr/lib/python3.6/site-packages/gaupol/agents/video.py
Line: 208
In: _on_play_selection_activate

    self.player.play_segment(start, end)

File: /usr/lib/python3.6/site-packages/gaupol/player.py
Line: 299
In: play_segment

    end = min(duration, self.calc.to_seconds(end)) * Gst.SECOND

TypeError: '<' not supported between instances of 'float' and 'NoneType'

Environment

Platform: Linux-4.11.9-1-ARCH-x86_64-with-arch
Locale: en_US.utf_8

Versions

aeidon: 1.2
chardet: 3.0.4
enchant: 1.6.8
gaupol: 1.2
gstreamer: 1.12.2.0
gtk+: 3.22.16
pygobject: 3.24.1
python: 3.6.1

[otsaloma]

Thanks, those actions should have been disabled, fixed now.