Cosmetical changes to ZIP source from merging changes to OpenCL.
ZIP-opencl: implement Jim's changes from CPU format.
ZIP formats: Bugfix for (unlikely) bad salts caught late. Actually
I think we should bail out with error in get_salt() instead but
this bugfix is needed as long as we handle it this way. Any real
problems are very unlikely though.
Drop some obsoleted variables from zip-opencl.
ZIP format: salt size fixes. Pot sync would not work without the
same quirk in cracker.c that RAR already had. And salt_hash()
should iterate over the entire salt.