Use 'visibleLength' if 'contentLength' is less

Summary: This prevents the 'distanceFromEnd' from being negative when 'offset' is zero, for example.
Closes https://github.com/facebook/react-native/pull/3074

Reviewed By: svcscm

Differential Revision: D2610771

Pulled By: sahrens

fb-gh-sync-id: f878f1c1b865063294013c3bb96b90831877d372

Libraries/CustomComponents/ListView/ListView.js

@@ -500,9 +500,11 @@ var ListView = React.createClass({
   },
 
   _getDistanceFromEnd: function(scrollProperties) {
-    return scrollProperties.contentLength -
-      scrollProperties.visibleLength -
-      scrollProperties.offset;
+    var maxLength = Math.max(
+      scrollProperties.contentLength,
+      scrollProperties.visibleLength
+    );
+    return maxLength - scrollProperties.visibleLength - scrollProperties.offset;
   },
 
   _updateVisibleRows: function(updatedFrames) {