use config. prefix in deploy scripts

This should fix these warning messages from EY:
WARNING: Use of `release_path` (via method_missing) is deprecated in favor of `config.release_path` for improved error messages and compatibility.
in /data/All_Our_Ideas/releases/20140313125531/deploy/before_migrate.rb
WARNING: Use of `shared_path` (via method_missing) is deprecated in favor of `config.shared_path` for improved error messages and compatibility.
in /data/All_Our_Ideas/releases/20140313125531/deploy/before_migrate.rb
WARNING: Use of `shared_path` (via method_missing) is deprecated in favor of `config.shared_path` for improved error messages and compatibility.
in /data/All_Our_Ideas/releases/20140313125531/deploy/before_migrate.rb
WARNING: Use of `release_path` (via method_missing) is deprecated in favor of `config.release_path` for improved error messages and compatibility.
in /data/All_Our_Ideas/releases/20140313125531/deploy/before_migrate.rb
WARNING: Use of `shared_path` (via method_missing) is deprecated in favor of `config.shared_path` for improved error messages and compatibility.
in /data/All_Our_Ideas/releases/20140313125531/deploy/before_migrate.rb
WARNING: Use of `release_path` (via method_missing) is deprecated in favor of `config.release_path` for improved error messages and compatibility.
in /data/All_Our_Ideas/releases/20140313125531/deploy/after_restart.rb
WARNING: Use of `node` (via method_missing) is deprecated in favor of `config.node` for improved error messages and compatibility.
in /data/All_Our_Ideas/releases/20140313125531/deploy/after_restart.rb
WARNING: Use of `node` (via method_missing) is deprecated in favor of `config.node` for improved error messages and compatibility.
in /data/All_Our_Ideas/releases/20140313125531/deploy/after_restart.rb
WARNING: Use of `release_path` (via method_missing) is deprecated in favor of `config.release_path` for improved error messages and compatibility.
in /data/All_Our_Ideas/releases/20140313125531/deploy/after_restart.rb