report extra files with warnings
report extra files with warnings

If the user forgets to add the .yaml extension, we ignore the
file. Instead of doing that silently, report that we see something and
that we're ignoring it.

Change-Id: I18130951a09a216339d3b63dc7decc67e766ee2d
Signed-off-by: Doug Hellmann <0798ebecfb7bc4dfb9d0445c2fa030eb64e1fa1c@doughellmann.com>

openstack/reno