[pitivi] previewers: Remove unused AudioPreviewer._start field

[Alexandru Băluț <alexbalut src gnome org>]

commit e618bef685f23d4922a76603e47d7863fb8fe4e6
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Mon Sep 17 06:15:12 2018 +0200

    previewers: Remove unused AudioPreviewer._start field

 pitivi/timeline/previewers.py | 2 --
 1 file changed, 2 deletions(-)
---
diff --git a/pitivi/timeline/previewers.py b/pitivi/timeline/previewers.py
index f6eb1e60..2e24f201 100644
--- a/pitivi/timeline/previewers.py
+++ b/pitivi/timeline/previewers.py
@@ -972,7 +972,6 @@ class AudioPreviewer(Previewer, Zoomable, Loggable):
         self.n_samples = asset.get_duration() / SAMPLE_DURATION
         self.samples = None
         self.peaks = None
-        self._start = 0
         self._end = 0
         self._surface_x = 0
 
@@ -1105,7 +1104,6 @@ class AudioPreviewer(Previewer, Zoomable, Loggable):
         end = int((drawn_start + drawn_duration) / SAMPLE_DURATION) + num_inpoint_samples
 
         if self._force_redraw or self._surface_x > clipped_rect.x or self._end < end:
-            self._start = start
             end = int(min(self.n_samples, end + (self.pixelToNs(MARGIN) /
                                                  SAMPLE_DURATION)))
             self._end = end