passenger: set minimum OS requirement to Lion.

This reverts a change introduced in a33585f9.
Passenger, up to the current version, builds fine in OS X 10.7.5.
passenger: update 4.0.50 bottle.

Closes #31941.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
Update virtualhost.sh formula to point to GitHub organization
virtualhost.sh: add 1.31 bottle.