drb: simplify shutdown pipe close logic
IO#close is idempotent, so we don't need to waste bytecode to check or nil it at shutdown time.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64531 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
drb: simplify shutdown pipe close logic
IO#close is idempotent, so we don't need to waste bytecode
to check or nil it at shutdown time.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64531 b2dd03c8-39d4-4d8f-98ff-823fe69b080e