Fix typo

src/bootstrap-table.js

@@ -902,7 +902,8 @@
                     cellStyle = {},
                     id_ = '',
                     class_ = that.header.classes[j];
-                    style = sprintf('style="%s"', csses.concat(that.header.styles[j]).join('; '));
+
+                style = sprintf('style="%s"', csses.concat(that.header.styles[j]).join('; '));
 
                 value = calculateObjectValue(that.header,
                     that.header.formatters[j], [value, item, i], value);