Merge pull request react-bootstrap#394 from mtetlow/master

Added check if we don't need to calc calculate the overlay position on mount

Author: mtscout6

src/OverlayTrigger.jsx

@@ -119,7 +119,9 @@ var OverlayTrigger = React.createClass({
   },
 
   componentDidMount: function() {
-    this.updateOverlayPosition();
+    if (this.props.defaultOverlayShown) {
+      this.updateOverlayPosition();
+    }
   },
 
   handleDelayedShow: function () {