Don't try to publish from www directory

The training-guides tox.ini was inherited from openstack-manuals
which merges static content from its www directory into its
publish-docs folder.

training-guides doesn't have a www directory -- it shares the static
content with openstack-manuals (they both publish into the same web
root).

Trying to copy files from a non-existent directory results in failure
which in turn prevents training-guides from publishing its manual.

This patch removes from tox.ini the commands that try to copy the
content of the www directory.

Closes-Bug: 1312764
Change-Id: I43f56523a7fe59d2d9ea92cabfcb4e926e751f6d