Some improvements request

Pull requests for following commints

* 38f6cd8 Fixed config.php installation directory to use node['virtualbox']['webportal']['installdir']
* d5e5b4f Added attribute
* 80e2a73 Changed phpVirtualBox password to use "rawpassword" value from data bag
* f16e06b Changed libshadow-ruby18 dependency to ruby-shadow gem

gem_package fix is for system that not use system-wide ruby but use /opt/chef