vcs.rb: env for command
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58387 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
vcs.rb: env for command
command paths by environment variables.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58387 b2dd03c8-39d4-4d8f-98ff-823fe69b080e