R1:d8e2bb9f0f51

Fix some straggling qsprintf() warnings in repository import

Summary:
Ref T13217. See <https://discourse.phabricator-community.org/t/unsafe-raw-string-warnings-while-importing-git-commits/2191>.

Hunt down and fix two more `qsprintf()` things.

I just converted the "performance optimization" into a normal, safe call since we're dealing with far less SVN stuff nowadays and the actual issue has been lost in the mists of time. If it resurfaces, we can take another look.

Test Plan: Imported some commits, no…