x11-themes/classiclooks: Attempt to fix build on CURRENT

unzip seems to fail extracting successfully due to insecure
symlink errors. Using tar instead seems to work fine.

Reported by: J.R. Oldroyd <fbsd@opal.com> (maintainer, via e-mail)
Reported by: pkg-fallout
Approved by: osa, vvd (Mentors, implicit)