Revert "check for hasCartesian && !hasPie for 'hovermode',"

This reverts commit e63ba4a.

Author: etpinard

src/components/modebar/buttons.js

@@ -500,7 +500,7 @@ function toggleHover(gd) {
     var fullLayout = gd._fullLayout;
 
     var onHoverVal;
-    if(fullLayout._hasCartesian && !fullLayout._hasPie) {
+    if(fullLayout._hasCartesian) {
         onHoverVal = fullLayout._isHoriz ? 'y' : 'x';
     }
     else onHoverVal = 'closest';

src/plots/cartesian/graph_interact.js

@@ -60,7 +60,7 @@ fx.supplyLayoutDefaults = function(layoutIn, layoutOut, fullData) {
     coerce('dragmode');
 
     var hovermodeDflt;
-    if(layoutOut._hasCartesian && !layoutOut._hasPie) {
+    if(layoutOut._hasCartesian) {
         // flag for 'horizontal' plots:
         // determines the state of the mode bar 'compare' hovermode button
         var isHoriz = layoutOut._isHoriz = fx.isHoriz(fullData);