[gnome-control-center] color: use Unicode in translatable strings

[Piotr Drąg <piotrdrag src gnome org>]

commit ce23ff67be9971374755e292a0c27e2fb45e153e
Author: Piotr Drąg <piotrdrag gmail com>
Date:   Mon Oct 3 14:39:02 2016 +0200

    color: use Unicode in translatable strings
    
    See https://developer.gnome.org/hig/stable/typography.html
    
    https://bugzilla.gnome.org/show_bug.cgi?id=772199

 panels/color/cc-color-calibrate.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/panels/color/cc-color-calibrate.c b/panels/color/cc-color-calibrate.c
index 0fed7b3..411bcb0 100644
--- a/panels/color/cc-color-calibrate.c
+++ b/panels/color/cc-color-calibrate.c
@@ -358,19 +358,19 @@ cc_color_calibrate_interaction_required (CcColorCalibrate *calibrate,
     case CD_SESSION_INTERACTION_ATTACH_TO_SCREEN:
       show_button_start = TRUE;
       /* TRANSLATORS: The user has to attach the sensor to the screen */
-      message_transl = _("Place your calibration device over the square and press 'Start'");
+      message_transl = _("Place your calibration device over the square and press “Start”");
       break;
     case CD_SESSION_INTERACTION_MOVE_TO_CALIBRATION:
       /* TRANSLATORS: Some calibration devices need the user to move a
        * dial or switch manually. We also show a picture showing them
        * what to do... */
-      message_transl = _("Move your calibration device to the calibrate position and press 'Continue'");
+      message_transl = _("Move your calibration device to the calibrate position and press “Continue”");
       break;
     case CD_SESSION_INTERACTION_MOVE_TO_SURFACE:
       /* TRANSLATORS: Some calibration devices need the user to move a
        * dial or switch manually. We also show a picture showing them
        * what to do... */
-      message_transl = _("Move your calibration device to the surface position and press 'Continue'");
+      message_transl = _("Move your calibration device to the surface position and press “Continue”");
       break;
     case CD_SESSION_INTERACTION_SHUT_LAPTOP_LID:
       /* TRANSLATORS: on some hardware e.g. Lenovo W700 the sensor