This reverts commit c702f76b271515e9c42dcb923d379fbfac4c83cd and turns it
into a documentation only fix. As it turns out, ENV should have never been
used at all, as the Rack docs say nothing about it *and* Passenger's
behaviour in 2.2.3 + 2.2.4 was completely broken and still is half-way broken
in 2.2.5 (but is OK with the Rack specs).

Fix #2386, by checking either Request.env or ENV for the SSL environment
variables. This is necessary as Passenger 2.2.3 changed the location of
these vars, even though the Rack spec says nothing about ENV or these
variables.

If you happen to already have puppet code somewhere in your ruby path, you
might get unexpected behaviour when trying to run puppetmaster with passenger.

Suggesting that the path to puppet/lib gets prepended instead of appended to
RUBYLIB could save time to some.

Signed-off-by: Marc Fournier <marc.fournier@camptocamp.com>