tests: fix up pure case of test-sqlitestore.t
This is clearly what the line should read based on the "force to zlib"
section below, so I'm guessing it just got overlooked during development.
Differential Revision: https://phab.mercurial-scm.org/D5151
tests: don't emit false failures when sqlite3 is missing
I'm honestly surprised we have buildbot coverage for this, but we do!
Differential Revision: https://phab.mercurial-scm.org/D5150