Homestyx hydra

R1:396be07c15b9

Add a setup issue about small "max_connections" settings

Summary:
Fixes T11683. Likely as a result of the persitent connections change, more users are seeing MySQL connection limit errors.

The persistent connections change means we use //fewer// connections at the high end, but I'm guessing PHP is keeping some more connections around in the pool, so while high-traffic hosts use fewer connections, low-traffic hosts now use more.

Raise an explicit setup warning about this. Users should be adjusting it…
Repository: R1 hydra
Commit Date: Sep 22 2016