v2.2.0

This is the 2.2.0 release, which contains:

• [#361] More graceful 503 handling
• [#364] Enforce http proxy support for calls to storage
• [#367] Stop disabling SELinux during provisioning
• [#377] Fix partition table race condition
• [#387] Fix latest version selection
• [#388] Fix extension substatus structure
• [#389] Fix shlex related update bug in Python 2.6
• [#391] Correct behavior of register-service
• [#398] AzureStack fixes
• [#400] Support xfs filesystem
• [#404] Correct service start/restart behavior
• [#411] Support for disabling provisioning
• [#417] Stop spamming journal with pidof dhlient related messages
• [#418] Add goal state processor to the version output
• [#425] Fix walinuxagent.service Want, After
• [#439] Ensure to load latest agents
• [#451] Correct proxy port type