title: Tooltip not working correctly with activeIndex on pie charts(ReCharts)
body: <p>Pie charts that utilize Tooltip and activeIndex do not work correctly. The tooltip will not show up unless you re-enter the same sector.
  When you are not in the same sector it shows the 
  Warning: Failed prop type: Invalid prop <code>activeIndex</code> supplied to <code>Pie</code>.</p>
  
  <pre><code>&lt;PieChart
          className="pie-chart"
          width={this.props.width ? this.props.width : 500}
          height={375}
          onMouseEnter={this.onPieEnter}
        &gt;
          &lt;Pie
            dataKey="value"
            data={data}
            // cx={250}
            // cy={100}
            activeIndex={
              this.state.activeIndex === undefined
                ? 0
                : this.state.activeIndex
            }
            activeShape={this.renderActiveShape}
            outerRadius={
              this.state.width &lt;= 1025 &amp;&amp; this.state.width &gt; 768 ? 80 : 100
            }
            innerRadius={
              this.state.width &lt;= 1025 &amp;&amp; this.state.width &gt; 768 ? 65 : 85
            }
            fill="#8884d8"
            onMouseEnter={this.onPieEnter}
          &gt;
            {data.map((entry, index) =&gt; (
              &lt;Cell
                key={index}
                fill={this.COLORS[index % this.COLORS.length]}
              /&gt;
            ))}
          &lt;/Pie&gt;
  &lt;/PieChart&gt;
  </code></pre>
  
  <p>Default active index always set so when you are not in the same sector
  pie tooltip shows.</p>