Have vfs_proxy search caches use dirmon framework to save handles

Have vfs_proxy search caches use dirmon framework to save handles

vfs_proxy was taking a file handle each time a search cache was
created on a directory.

This became a very large number if a ffirst was done on each file
in a large directory and could cause the windows server to close
the connection due to an abusive client.

The simple fix is to have search caches use the dirmon framework
that was since developed