DatePickers: Remove enforcing start date min.

You might want to edit conference metadata after the start date has past, so it is
logical to allow the start date to be earlier than "today". As there are no backend
validations, this change is safe and removes a UI bug.

app/assets/javascripts/osem-datepickers.js

@@ -1,5 +1,3 @@
-// get current_date
-var today = new Date().toISOString().slice(0, 10);
 $(function () {
   $("input[id^='datetimepicker']").datetimepicker({
     useCurrent: false,
@@ -18,9 +16,8 @@ $(function () {
       stepping: 15,
       sideBySide: true,
       format: "YYYY-MM-DD HH:mm",
-      // current_date <= arrival_date <= end_date
-      maxDate : $("#registration-arrival-datepicker").attr('end_date'),
-      minDate : today
+      // arrival_date <= end_date
+      maxDate : $("#registration-arrival-datepicker").attr('end_date')
   });
 
   $("#registration-departure-datepicker").datetimepicker({
@@ -49,9 +46,7 @@ $(function () {
 
    $("#conference-start-datepicker").datetimepicker({
        useCurrent: false,
-       format: "YYYY-MM-DD",
-       // conference-start-day >= Current_date
-       minDate : today
+       format: "YYYY-MM-DD"
    });
 
    $("#conference-end-datepicker").datetimepicker({
@@ -59,18 +54,16 @@ $(function () {
        format: "YYYY-MM-DD"
    });
 
-   // today <= start_registration <= end_registration <= end_conference
+   // start_registration <= end_registration <= end_conference
    var end_conference = $('form').data('end-conference');
 
    $('#registration-period-start-datepicker').datetimepicker({
        format: 'YYYY-MM-DD',
-       minDate : today,
        maxDate : end_conference
    });
 
    $('#registration-period-end-datepicker').datetimepicker({
        format: 'YYYY-MM-DD',
-       minDate : today,
        maxDate : end_conference
    });