Merge pull request banchichen#1663 from coderAs7/master

修复会出现两个noDataLabel的问题

Author: banchichen

TZImagePickerController/TZImagePickerController/TZPhotoPickerController.m

@@ -204,6 +204,10 @@ - (void)configCollectionView {
 
     _collectionView.contentSize = CGSizeMake(self.view.tz_width, (([self getAllCellCount] + self.columnNumber - 1) / self.columnNumber) * self.view.tz_width);
     if (_models.count == 0) {
+        if (_noDataLabel) {
+            [_noDataLabel removeFromSuperview];
+            _noDataLabel = nil;
+        }
         _noDataLabel = [UILabel new];
         _noDataLabel.textAlignment = NSTextAlignmentCenter;
         _noDataLabel.text = [NSBundle tz_localizedStringForKey:@"No Photos or Videos"];