Add some logging when cache gets cleaned.
Wrong key was used, so every active connection did a clean for the same new AIS.
Merge branch 'preptime-query-context' into pg-statement-cache
Invalidate old statement caches right away.
merge MMcM: Tighten up statement cache handling a little

Merge pull request #1208 from MMcM/sql-layer/pg-statement-cache
https://github.com/FoundationDB/sql-layer/pull/1208