Fix nil attribute in cron recipe.
Fix nil attribute in cron recipe.

Signed-off-by: Nathan Cerny <0fbb4d839a02945eeea4f5af362a0e7a17840b12@gmail.com>

chef-cookbooks/chef-client,opscode-cookbooks/chef-client,mattray/chef-client,opscode-cookbooks/chef-client,scalp42/chef-client,scalp42/chef-client,mattray/chef-client,juliandunn/chef-client,juliandunn/chef-client,scalp42/chef-client,mattray/chef-client,opscode-cookbooks/chef-client,juliandunn/chef-client,chef-cookbooks/chef-client,chef-cookbooks/chef-client