Use rhnPackage.path as rhnErrataFile.filename like Perl does
Fail if rhnPackage.path is NULL

This can only happen as a result of running spacewalk-data-fsck when a package is not found on the filesystem.
In that case, it should not be published either, instead the filesystem should be fixed and
spacewalk-data-fsck should be run again before publishing.
Avoid trimming filename to 128 chars

Current database and OS limitation is 4K, so this does not make sense anymore.
Fail if rhnPackage.path is NULL

This can only happen as a result of running spacewalk-data-fsck when a package is not found on the filesystem.
In that case, it should not be published either, instead the filesystem should be fixed and
spacewalk-data-fsck should be run again before publishing.