Don't crash when opening a file while an SVN operation is in progress.

http://community.sharpdevelop.net/forums/t/15766.aspx

src/AddIns/VersionControl/SubversionAddIn/Src/Gui/ProjectBrowserVisitor/OverlayIconManager.cs

@@ -192,7 +192,12 @@ namespace ICSharpCode.Svn
 					}
 				}
 				
-				return client.SingleStatus(fileName).TextStatus;
+				try {
+					return client.SingleStatus(fileName).TextStatus;
+				} catch (SvnClientException ex) {
+					LoggingService.Warn(ex);
+					return StatusKind.None;
+				}
 			}
 		}