Ruby » Ruby master

git-refresh: fix abort by cd failure

• tool/git-refresh: try cd -P in a subshell, because Solaris10
  sh dies if it fails, not only the command.
  [ruby-dev:50074] [Bug #13433]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58344 b2dd03c8-39d4-4d8f-98ff-823fe69b080e