[gnome-calculator] Do not convert on swap (fixes #170)

[Robert Roth <robertroth src gnome org>]

commit f2231b510d76f95d7596dd4b6d6b6d23be5df500
Author: Robert Roth <robert roth off gmail com>
Date:   Sat Oct 17 20:12:45 2020 +0300

    Do not convert on swap (fixes #170)

 src/math-converter.vala | 2 --
 1 file changed, 2 deletions(-)
---
diff --git a/src/math-converter.vala b/src/math-converter.vala
index 802a069a..bc03b4de 100644
--- a/src/math-converter.vala
+++ b/src/math-converter.vala
@@ -236,8 +236,6 @@ public class MathConverter : Gtk.Grid
         set_active_unit (from_combo, null, to_unit);
         set_active_unit (to_combo, null, from_unit);
 
-        do_convert(out from_unit, out to_unit);
-
         update_result_label ();
     }