mediawiki: adjust hhvm max threads to number of cpus as well

It seems HHVM can't work well whenever its thread count gets very high
compared to the available processors, so we also limit the max number of
running threads based on that as well.

This would result in:
* 96 threads on smaller appservers (we had 100)
* 128 threads on larger appservers (we had 536)

Change-Id: I204c55c5bea378ccbf65a363cfc8ad29b29bea27
Signed-off-by: Giuseppe Lavagetto <glavagetto@wikimedia.org>
toollabs: lint

Change-Id: If7d9eda0fef5ca8a961021bb1bd21f01b8aa7e93
Merge "toollabs: lint" into production