Revert r36213 "popen: shell commands with envvar"
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36218 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Revert r36213 "popen: shell commands with envvar"
envvar" because it disabled to let single command bypass shell.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36218 b2dd03c8-39d4-4d8f-98ff-823fe69b080e