Added missing openssl dependency

Without this, the following error occurred:

```
================================================================================
Recipe Compile Error in /home/jan/chef/cookbooks/phpmyadmin/recipes/default.rb
================================================================================

NameError
---------
uninitialized constant Opscode::OpenSSL

Cookbook Trace:
---------------
  /home/jan/chef/cookbooks/phpmyadmin/recipes/configuration.rb:1:in `from_file'
  /home/jan/chef/cookbooks/phpmyadmin/recipes/default.rb:3:in `from_file'

Relevant File Content:
----------------------
/home/jan/chef/cookbooks/phpmyadmin/recipes/configuration.rb:

  1>> ::Chef::Recipe.send(:include, Opscode::OpenSSL::Password)
  2:  
  3:  # generate all passwords
  4:  node.set_unless[:phpmyadmin][:cfg][:blowfish_secret]          =   secure_password()
  5:  node.set_unless[:phpmyadmin][:cfg][:control_user_password]    =   secure_password()
  6:  
  7:  template "#{node[:phpmyadmin][:cfg][:cfg_path]}/config-db.php" do
  8:    source "phpmyadmin/config-db.php.erb"
  9:    owner "root"
 10:    group "root"