Remove 'node' parameter from the Deploy interface

The node parameter is redundant since the node object is an attribute
of the task object.

In the PXE driver, the helper functions _create_token_file,
_remove_internal_attrs, _update_neutron and _create_pxe_config were also
updated removing the 'node' parameter from the function definition.

Partial-Bug: #1312632
Change-Id: I82b3078c00cdf6e417c3f379bf03f1c5cae533d7