[REF] Minor var simplification

[eileenmcnaughton]

Overview

Slight code clarification

Before

Determination of $update less explicit

After

Defined once, an else used later

Technical Details

@mattwire this is pretty minor but I spotted it looking at your proposal. Note I brought in a couple of small changes from yours to reduce the code in any one change

Comments

[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).

[colemanw]

Merging based on code review & passing tests.