SUP-2582, Upcoming SRMs should be ordered by most recent date

-- Incorporated code review comments

Author: vikasrohit

app/my-dashboard/srms/srms.controller.js

@@ -21,7 +21,8 @@
 
     function getSRMs() {
       var params = {
-        filter: 'status=future&orderBy=registrationStartAt',
+        filter: 'status=future',
+        orderBy: 'registrationStartAt',
         limit: 3
       };
 

app/my-srms/my-srms.controller.js

@@ -52,6 +52,8 @@
 
     function changeFilter(filter) {
       vm.statusFilter = filter;
+      // for upcoming SRMs sorting is done ascending order of codingStartAt
+      // for past SRMs sorting is done descending order of codingEndAt
       vm.orderBy = filter === 'future'? 'codingStartAt': 'codingEndAt';
       vm.reverseOrder = filter !== 'future';
       // update url but don't reload