fix(datepicker): min-date: strip time on literals

fixes angular-ui#3437

Author: davious

Diff for: src/datepicker/datepicker.js

@@ -618,7 +618,13 @@ function(scope, element, attrs, $compile, $parse, $document, $rootScope, $positi
         scope.$parent.$watch(getAttribute, function(value) {
           scope.watchData[key] = value;
           if (key === 'minDate' || key === 'maxDate') {
-            cache[key] = new Date(value);
+            var date = parseDate(value);
+            if(!date) {
+              var dateArray = new Date(value).toISOString().split('T')[0].split('-');
+              date = new Date(+dateArray[0], +dateArray[1] - 1, +dateArray[2]);
+            }
+            scope.watchData[key] = date;
+            cache[key] = date;
           }
         });
         datepickerEl.attr(cameltoDash(key), 'watchData.' + key);