fix logging when we don't want ppa updates and or don't have internet access
Fix unnecessary error messages in log when default['openstack']['apt']['components'] attribute is nil or empty.

Currently if you are working in an environment that cannot reach the target openstack-ppa uri/components, say you do not have internet access for instance, you will see the following error in the log:

[2014-02-23T17:30:06-06:00] INFO: Processing apt_repository[openstack-ppa] action add (openstack-common::default line 35)
[2014-02-23T17:30:06-06:00] INFO: Processing file[/var/lib/apt/periodic/update-success-stamp] action nothing (/var/chef/cookbooks/apt/providers/repository.rb line 106)
[2014-02-23T17:30:06-06:00] INFO: Processing execute[apt-cache gencaches] action nothing (/var/chef/cookbooks/apt/providers/repository.rb line 110)
[2014-02-23T17:30:06-06:00] INFO: Processing execute[apt-get update] action nothing (/var/chef/cookbooks/apt/providers/repository.rb line 115)
[2014-02-23T17:30:06-06:00] INFO: Processing file[/etc/apt/sources.list.d/openstack-ppa.list] action create (/var/chef/cookbooks/apt/providers/repository.rb line 132)
[2014-02-23T17:30:06-06:00] INFO: file[/etc/apt/sources.list.d/openstack-ppa.list] created file /etc/apt/sources.list.d/openstack-ppa.list
[2014-02-23T17:30:06-06:00] INFO: file[/etc/apt/sources.list.d/openstack-ppa.list] updated file contents /etc/apt/sources.list.d/openstack-ppa.list
[2014-02-23T17:30:06-06:00] INFO: file[/etc/apt/sources.list.d/openstack-ppa.list] owner changed to 0 [2014-02-23T17:30:06-06:00] INFO: file[/etc/apt/sources.list.d/openstack-ppa.list] group changed to 0
[2014-02-23T17:30:06-06:00] INFO: file[/etc/apt/sources.list.d/openstack-ppa.list] mode changed to 644 [2014-02-23T17:30:06-06:00] INFO: file[/etc/apt/sources.list.d/openstack-ppa.list] sending delete action to file[/var/lib/apt/periodic/update-success-stamp] (immediate) [2014-02-23T17:30:06-06:00] INFO: Processing file[/var/lib/apt/periodic/update-success-stamp] action delete (/var/chef/cookbooks/apt/providers/repository.rb line 106)
[2014-02-23T17:30:06-06:00] INFO: file[/etc/apt/sources.list.d/openstack-ppa.list] sending run action to execute[apt-get update] (immediate)
[2014-02-23T17:30:06-06:00] INFO: Processing execute[apt-get update] action run (/var/chef/cookbooks/apt/providers/repository.rb line 115)
[2014-02-23T17:30:06-06:00] ERROR: execute[apt-get update] (/var/chef/cookbooks/apt/providers/repository.rb line 115) had an error:
Expected process to exit with [0], but received '100' ---- Begin output of apt-get update -o Dir::Etc::sourcelist='sources.list.d/openstack-ppa.list' -o
Dir::Etc::sourceparts='-' -o APT::Get::List-Cleanup='0' ---- STDOUT: Ign http://ubuntu-cloud.archive.canonical.com precise-updates/havana Release.gpg Ign http://ubuntu-cloud.archive.canonical.com precise-updates/havana Release
Ign http://ubuntu-cloud.archive.canonical.com precise-updates/havana/main TranslationIndex Err http://ubuntu-cloud.archive.canonical.com precise-updates/havana/main amd64 Packages
  502 Proxy Error [IP: fccd:5585:47e0:1:ecb1:4916:eb0:3bd6 8123] Err http://ubuntu-cloud.archive.canonical.com precise-updates/havana/main i386 Packages
  502 Proxy Error [IP: fccd:5585:47e0:1:ecb1:4916:eb0:3bd6 8123] Ign http://ubuntu-cloud.archive.canonical.com precise-updates/havana/main Translation-en STDERR: W: Failed to fetch
http://ubuntu-cloud.archive.canonical.com/ubuntu/dists/precise-updates/havana/main/binary-amd64/Packages 502 Proxy Error [IP: fccd:5585:47e0:1:ecb1:4916:eb0:3bd6 8123] W: Failed to fetch
http://ubuntu-cloud.archive.canonical.com/ubuntu/dists/precise-updates/havana/main/binary-i386/Packages 502 Proxy Error [IP: fccd:5585:47e0:1:ecb1:4916:eb0:3bd6 8123] E: Some index files failed to download. They have been
ignored, or old ones used instead. ---- End output of apt-get update -o Dir::Etc::sourcelist='sources.list.d/openstack-ppa.list' -o Dir::Etc::sourceparts='-' -o APT::Get::List-Cleanup='0' ---- Ran apt-get update -o
Dir::Etc::sourcelist='sources.list.d/openstack-ppa.list' -o Dir::Etc::sourceparts='-' -o APT::Get::List-Cleanup='0' returned 100; ignore_failure is set, continuing

================================================================================
 Error executing action `run` on resource 'execute[apt-get update]' ================================================================================

Mixlib::ShellOut::ShellCommandFailed ------------------------------------ Expected process to exit with [0], but received '100' ---- Begin output of apt-get update -o Dir::Etc::sourcelist='sources.list.d/openstack-ppa.list' -o
Dir::Etc::sourceparts='-' -o APT::Get::List-Cleanup='0' ---- STDOUT: Ign http://ubuntu-cloud.archive.canonical.com precise-updates/havana Release.gpg Ign http://ubuntu-cloud.archive.canonical.com precise-updates/havana Release
Ign http://ubuntu-cloud.archive.canonical.com precise-updates/havana/main TranslationIndex Err http://ubuntu-cloud.archive.canonical.com precise-updates/havana/main amd64 Packages
  502 Proxy Error [IP: fccd:5585:47e0:1:ecb1:4916:eb0:3bd6 8123] Err http://ubuntu-cloud.archive.canonical.com precise-updates/havana/main i386 Packages
  502 Proxy Error [IP: fccd:5585:47e0:1:ecb1:4916:eb0:3bd6 8123] Ign http://ubuntu-cloud.archive.canonical.com precise-updates/havana/main Translation-en STDERR: W: Failed to fetch
http://ubuntu-cloud.archive.canonical.com/ubuntu/dists/precise-updates/havana/main/binary-amd64/Packages 502 Proxy Error [IP: fccd:5585:47e0:1:ecb1:4916:eb0:3bd6 8123] W: Failed to fetch
http://ubuntu-cloud.archive.canonical.com/ubuntu/dists/precise-updates/havana/main/binary-i386/Packages 502 Proxy Error [IP: fccd:5585:47e0:1:ecb1:4916:eb0:3bd6 8123] E: Some index files failed to download. They have been
ignored, or old ones used instead. ---- End output of apt-get update -o Dir::Etc::sourcelist='sources.list.d/openstack-ppa.list' -o Dir::Etc::sourceparts='-' -o APT::Get::List-Cleanup='0' ---- Ran apt-get update -o
Dir::Etc::sourcelist='sources.list.d/openstack-ppa.list' -o Dir::Etc::sourceparts='-' -o APT::Get::List-Cleanup='0' returned 100

Resource Declaration: ---------------------
115: execute 'apt-get update' do 116: command "apt-get update -o Dir::Etc::sourcelist='sources.list.d/#{new_resource.name}.list' -o Dir::Etc::sourceparts='-' -o APT::Get::List-Cleanup='0'" 117: ignore_failure true 118: action
:nothing
119: notifies :run, 'execute[apt-cache gencaches]', :immediately 120: end 121:

Compiled Resource: ------------------
execute("apt-get update") do
  action [:nothing]
  ignore_failure true
  retries 0
  retry_delay 2
  command "apt-get update -o Dir::Etc::sourcelist='sources.list.d/openstack-ppa.list' -o Dir::Etc::sourceparts='-' -o APT::Get::List-Cleanup='0'"
  backup 5
  returns 0
  cookbook_name :"openstack-common" end

The user should be able to set default['openstack']['apt']['components'] = nil to avoid this error but doing so leads to another exception.

This patch intended to avoid executing an unnesessary code path by checking first checking if this attribute is nil or empty prior to attempting to fetch updates.
remove change to ['openstack']['apt']['components'] attribute
Add custom cookbook for setting ['openstack']['apt']['components'] to nil instead of setting upstream attributes file.
have to set attribute to [] instead of nil, override ignores set to nil
Reverse positions in run list so override set before os-base role executes
Merge pull request #67 from dpaterson/pull-req-master-8c9e97711bb27de6c8e942d5bd8a5e68d4dddb03

Fix unnecessary error messages in log when default['openstack']['apt']['components'] attribute is nil or empty. [1/1]