QPID-4095: Move the directory iteration into FileSysDir:
- For Posix implement with direct calls
- For windows implement with v2/v3 boost::filesystem to be replaced later

[Cherry picked from trunk@1424247]

git-svn-id: https://svn.apache.org/repos/asf/qpid/branches/0.20@1430554 13f79535-47bb-0310-9956-ffa450edef68