Change "Database schema" to "Database updates" in admin status report

In the status report on the Administer page, system_requirements() creates an entry titled "Database schema" that either says "Up to date" or reports that there are updates to perform. The entry does not really know whether the schema is correct; it knows that there are updates to perform. I'd like to change it to say "Database updates" instead.

The reason I care, of course, is that schema.module can put a "Database schema" entry in the status report that actually reports on the correctness of the database schema. It would be silly to have two entries for "Database schema", one that says "Up to date" and one that might report inconsistencies.

One-line patch attached; all it does is change a string.