[gnome-calculator] Use currency name instead of display name for conversion (fixes #106)

[Robert Roth <robertroth src gnome org>]

commit a59b98cf9a241b37c42d56482afaace4783483f5
Author: Robert Roth <robert roth off gmail com>
Date:   Wed Mar 27 01:55:05 2019 +0200

    Use currency name instead of display name for conversion (fixes #106)

 src/math-converter.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/math-converter.vala b/src/math-converter.vala
index a83dea24..ee335891 100644
--- a/src/math-converter.vala
+++ b/src/math-converter.vala
@@ -244,7 +244,7 @@ public class MathConverter : Gtk.Grid
             var z = convert_equation (x, out from_unit, out to_unit);
             if (z != null && from_unit != null && to_unit != null)
             {
-                equation.set ("%s %s %s %s".printf(equation.serializer.to_string (x), 
from_unit.display_name, _("in"), to_unit.display_name));
+                equation.set ("%s %s %s %s".printf(equation.serializer.to_string (x), from_unit.name, 
_("in"), to_unit.name));
                 equation.solve ();
             }
         }