[gnome-subtitles] Fix #112 - negative time shift not work

[Pedro Castro <pcastro src gnome org>]

commit b425e8d15a7ef42d54249cce836fb91fdcc1376c
Author: Pedro Castro <pedro gnomesubtitles org>
Date:   Sun Oct 28 17:15:49 2018 +0000

    Fix #112 - negative time shift not work

 src/GnomeSubtitles/Dialog/TimingsShiftDialog.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/GnomeSubtitles/Dialog/TimingsShiftDialog.cs b/src/GnomeSubtitles/Dialog/TimingsShiftDialog.cs
index dcd17ce..1131e8d 100644
--- a/src/GnomeSubtitles/Dialog/TimingsShiftDialog.cs
+++ b/src/GnomeSubtitles/Dialog/TimingsShiftDialog.cs
@@ -226,7 +226,7 @@ public class TimingsShiftDialog : BaseDialog {
 
        protected override bool ProcessResponse (ResponseType response) {
                if (response == ResponseType.Ok) {
-                       if (spinButton.ValueAsInt > 0) {
+                       if (spinButton.ValueAsInt != 0) {
                                SelectionIntended selectionIntended = GetSelectionIntended();
        
                                if (timingMode == TimingMode.Times) {