[pitivi] viewer: Remove relief for play button

[Alexandru Băluț <alexbalut src gnome org>]

commit 27f6238ca8af60e17c4d2ea10b6d696b16cde9dc
Author: Diego Garcia Gangl <dnicolas gmail com>
Date:   Sat Apr 20 20:14:32 2019 -0300

    viewer: Remove relief for play button

 pitivi/viewer/viewer.py | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/pitivi/viewer/viewer.py b/pitivi/viewer/viewer.py
index 8e1b093c..7932840b 100644
--- a/pitivi/viewer/viewer.py
+++ b/pitivi/viewer/viewer.py
@@ -703,6 +703,7 @@ class PlayPauseButton(Gtk.Button, Loggable):
         Loggable.__init__(self)
         self.image = Gtk.Image()
         self.add(self.image)
+        self.set_relief(Gtk.ReliefStyle.NONE)
         self.playing = False
         self.setPlay()