Graph: improved decimal precision in legend and graph hover when graph ticks use…

Graph: improved decimal precision in legend and graph hover when graph ticks use single decimal point, now graph legend and tooltip always use one more decimal precision than axis ticks (if axis ticks has decimals), Fixes #1072

src/app/panels/graph/graph.js

@@ -115,7 +115,12 @@ function (angular, $, kbn, moment, _, GraphTooltip) {
             var series = data[i];
             var series = data[i];
             var axis = yaxis[series.yaxis - 1];
             var axis = yaxis[series.yaxis - 1];
             var formater = kbn.valueFormats[scope.panel.y_formats[series.yaxis - 1]];
             var formater = kbn.valueFormats[scope.panel.y_formats[series.yaxis - 1]];
-            series.updateLegendValues(formater, axis.tickDecimals, axis.scaledDecimals + 2);
+
+            // legend and tooltip gets one more decimal precision
+            // than graph legend ticks
+            var tickDecimals = (axis.tickDecimals || -1) + 1;
+
+            series.updateLegendValues(formater, tickDecimals, axis.scaledDecimals + 2);
             if(!scope.$$phase) { scope.$digest(); }
             if(!scope.$$phase) { scope.$digest(); }
           }
           }
         }
         }