by Tatsuhiko Miyagawa, using 'if (__FILE__ eq $0)' in .psgi code
(to check if script was run from command line), is not supposed to work
since Plack 0.9971.
Replace it with one of proposed solutions; while at it return $app
explicitely, rather than implicitely by being a last expression.
This affects 'plackup' web server.
While at it cleanup whitespace.
Signed-off-by: Jakub Narebski <jnareb@gmail.com> Acked-by: Eric Wong <normalperson@yhbt.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>