Update SFDC handler.

A number of changes to the Salesforce handler:

* Cache OAuth token if `token_cache_file` option is present in config.
    - This is to avoid repeated logins, which Salesforce ratelimits.
    - Optional, if config option is not present it will default to old
      behavior of logging in each time.

* Close alerts on recovery
    - If a recovery alert is sent, mark the Salesforce MOS Alert as
      "Solved"

* Cosmetic changes to the alert body text:
    - make subject line more clear (remove the cloud id)
    - format the description and feed items (instead of just dumping
      json)

* Bug fix around `check_action` sometimes being unicode, but code checks
  for `str` specifically.

Change-Id: I05b6f9834d556d199310974db68cd403cab4e403
2 files changed