Reevaluate behavior of manta.skip_directory_depth greater than depth of directory to be created

[tjcelaya]

Currently users can attempt to skip a fixed number of directory creation steps when utilizing the recursive option to MantaClient#putDirectory. As a precaution the initial implementation of this feature reverted to the standard behavior when the setting was tuned too high, e.g. creating /user/stor/foo/bar/baz with the setting at 10 would create all parts (.../foo, .../foo/bar, .../foo/bar/baz).

We can improve this slightly be treating the writeableDirectories <= skipDepth case as "try to create the requested directory directly, then fall back to creating all parts if that fails." Effectively, turning the setting up to a ridiculous number would cause recursive putDirectory calls to behave as if every intermediate directory already existed.

More clearly phrased, if we set manta.skip_directory_depth to 100 any attempts to create recursively directories with less than 100 segments will begin by attempting to create just the requested path (falling back to creating all intermediate directories if that fails).