fix(datepicker): fix today button disabled condition

- Fix conditional for today button in popup

Closes #5637
Fixes #5622

Author: wesleycho

src/datepicker/datepicker.js

@@ -1013,11 +1013,17 @@ function($scope, $element, $attrs, $compile, $log, $parse, $window, $document, $
 
   $scope.isDisabled = function(date) {
     if (date === 'today') {
-      date = new Date();
+      date = dateParser.fromTimezone(new Date(), ngModelOptions.timezone);
+    }
+
+    if ($scope.datepickerOptions) {
+      return $scope.datepickerOptions &&
+        $scope.datepickerOptions.minDate && $scope.compare(date, $scope.datepickerOptions.minDate) < 0 ||
+        $scope.datepickerOptions.maxDate && $scope.compare(date, $scope.datepickerOptions.maxDate) > 0;
     }
 
     return $scope.watchData.minDate && $scope.compare(date, cache.minDate) < 0 ||
-        $scope.watchData.maxDate && $scope.compare(date, cache.maxDate) > 0;
+      $scope.watchData.maxDate && $scope.compare(date, cache.maxDate) > 0;
   };
 
   $scope.compare = function(date1, date2) {