Camino only - Bug 377192: Fix crash when dragging text to a tab. r/sr=josh

camino/src/browser/BrowserTabView.mm

@@ -426,7 +426,7 @@ NSString* const kTabBarBackgroundDoubleClickedNotification = @"kTabBarBackground
 {
   [self hideDragDestinationIndicator];
 
-  NSArray* urls;
+  NSArray* urls = nil;
   NSArray* pasteBoardTypes = [[sender draggingPasteboard] types];
   if ([pasteBoardTypes containsObject:kCaminoBookmarkListPBoardType]) {
     NSArray* bookmarkUUIDs = [[sender draggingPasteboard] propertyListForType:kCaminoBookmarkListPBoardType];