Fix verb tense in update function summaries

Noticed in #1833022-165: Only display interface language detection options to customize more granularity

Problem/Motivation

https://drupal.org/node/1354

Update functions (implementations of hook_update_N())
These use a different syntax, because the documentation summary (first line) is displayed to someone running update.php to tell them which updates need to run.

Note that the first line should start with an imperative verb, so it will make sense to people running update.php.

Proposed resolution

correct verb tense so they make sense during updates.

Remaining tasks

TBD.

User interface changes

No.

API changes

No.