Update datepicker.js

Fix for issue angular-ui#2789 where it was throwing "$apply already in progress" when using ng-focus to open the popup.

src/datepicker/datepicker.js

@@ -524,6 +524,13 @@ function ($compile, $parse, $document, $position, dateFilter, dateParser, datepi
       }
       ngModel.$parsers.unshift(parseDate);
 
+      function closeWithFocus() {
+        $timeout(function () {
+          scope.isOpen = false;
+          element[0].focus();
+        }, 0, false);
+      }
+
       // Inner change
       scope.dateSelection = function(dt) {
         if (angular.isDefined(dt)) {
@@ -533,8 +540,7 @@ function ($compile, $parse, $document, $position, dateFilter, dateParser, datepi
         ngModel.$render();
 
         if ( closeOnDateSelection ) {
-          scope.isOpen = false;
-          element[0].focus();
+          closeWithFocus();
         }
       };
 
@@ -600,8 +606,7 @@ function ($compile, $parse, $document, $position, dateFilter, dateParser, datepi
       };
 
       scope.close = function() {
-        scope.isOpen = false;
-        element[0].focus();
+        closeWithFocus();
       };
 
       var $popup = $compile(popupEl)(scope);