Fixes VM extend retirement

The retires_on field was changed from a `:date` column to a `:datetime`
which now requires the days(in seconds) be added to the time.

- Depends on: ManageIQ/manageiq#14143
- This issue was introduced in PR ManageIQ/manageiq#11156
- https://bugzilla.redhat.com/show_bug.cgi?id=1427503

Signed-off-by: Sachin <psachin@redhat.com>

content/automate/ManageIQ/Cloud/VM/Retirement/Email.class/__methods__/vm_retire_extend.rb

@@ -30,7 +30,7 @@
   $evm.log("info", "Extending retirement <#{vm_retire_extend_days}> days for VM: <#{vm_name}>")
 
   # Set new retirement date here
-  vm.retires_on += vm_retire_extend_days.to_i
+  vm.extend_retires_on(vm_retire_extend_days, vm.retires_on)
 
   $evm.log("info", "VM: <#{vm_name}> new retirement date is #{vm.retires_on}")
 

content/automate/ManageIQ/Infrastructure/VM/Retirement/Email.class/__methods__/vm_retire_extend.rb

@@ -32,7 +32,7 @@
   $evm.log("info", "Extending retirement <#{vm_retire_extend_days}> days for VM: <#{vm_name}>")
 
   # Set new retirement date here
-  vm.retires_on += vm_retire_extend_days.to_i
+  vm.extend_retires_on(vm_retire_extend_days, vm.retires_on)
 
   $evm.log("info", "VM: <#{vm_name}> new retirement date is #{vm.retires_on}")