Set the smarty variables for mem_status and mem_join_date for back-end membership renewals

[agileware-justin]

Overview

Set the smarty variables for mem_status and mem_join_date for back-end membership renewals.

Before

mem_status and mem_join_date are not available for back-end membership renewals. Which is problematic when trying to use the mem_status variable to display a "Thanks for renewing!" message or a "Welcome new member" when using the Memberships - Signup and Renewal Receipts (off-line) message template.

After

smarty variables for mem_status and mem_join_date are now available.

Technical Details

Comments

Agileware Ref: CIVICRM-1729

[civibot]

(Standard links)

• If this is your first pull-request for CiviCRM, please browse CONTRIBUTING.md for information about the development and testing processes.
• If you are reviewing this pull-request, you may wish to consult the test sites and the Review Standards (long template, short template).

[mattwire]

We should be moving away from using smarty variables in favour of tokens in messagetemplates but we are a way off that yet (at least for memberships). These parameters should probably be locked in with a test but it's silly that some are passed in and others not.
I'm merging this because it makes it consistent with the more "standard" Contribution.sendconfirmation API and other contribution/membership workflows that send emails. Future cleanups will then be able to work with a consistent set of params.