test_command_processor.rb: clear tmpdir

* test/shell/test_command_processor.rb (TestShell#teardown): should
  not leave temporary directories.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43537 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
pty.c: check error of seteuid

* ext/pty/pty.c (chfunc): check error of seteuid and return error
  message, to suppress unused-value warning.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43538 b2dd03c8-39d4-4d8f-98ff-823fe69b080e