From @fpletz: Keep poolConfigs option for backwards-compatibility.
The original commit 6b3f5b5a421fe3422e9ef63a3fd690178c36163e was previously
reverted by c7860cae1a4b54f4b54339142472f00f861fa055 but the issues were
resolved.
This reverts commit 6b3f5b5a421fe3422e9ef63a3fd690178c36163e because it
introduced a non-backwards compatible change in the phpfpm interface,
without really needing to. The new interface, if needed, can be re-added
alongside the old interface.
Commit 98e419c0e27dd21e9dee0b915876ea60 ("tt-rss service: init at 16.3")
depends on the new interface, so this commit updates the tt-rss service
to work with the old services.phpfpm.poolConfigs interface.