[banshee] [Audioscrobbler] Ignore negative increase for playtime calculation

[Bertrand Lorentz <blorentz src gnome org>]

commit 58746e17dc4309aa33a644c75669f6b8262fdc82
Author: Bertrand Lorentz <bertrand lorentz gmail com>
Date:   Tue Jun 2 22:19:34 2009 +0200

    [Audioscrobbler] Ignore negative increase for playtime calculation
    
    This fixes the issue in bgo#584614. A negative increase would happen
    after skipping a track, because there's an Iterate event on the new
    track before the StartOfStream event for it.
---
 .../AudioscrobblerService.cs                       |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/src/Extensions/Banshee.Lastfm/Banshee.Lastfm.Audioscrobbler/AudioscrobblerService.cs b/src/Extensions/Banshee.Lastfm/Banshee.Lastfm.Audioscrobbler/AudioscrobblerService.cs
index d951b69..6813f6d 100644
--- a/src/Extensions/Banshee.Lastfm/Banshee.Lastfm.Audioscrobbler/AudioscrobblerService.cs
+++ b/src/Extensions/Banshee.Lastfm/Banshee.Lastfm.Audioscrobbler/AudioscrobblerService.cs
@@ -186,7 +186,9 @@ namespace Banshee.Lastfm.Audioscrobbler
                 
                 if (ignorenext == 0) {
                     increase = (ServiceManager.PlayerEngine.Position - previouspos);
-                    playtime += increase;
+                    if (increase > 0) {
+                        playtime += increase;
+                    }
                 } else {
                     ignorenext--;
                 }