Bug 1014524 - Report update hotfix results in FHR; r=rnewman

The v20140527.01 update hotfix deposited a JSON file in the profile
directory containing state. This file was purposefully not deleted
during hotfix uninstall so its contents could be later reported in
FHR.

This patch adds that reporting to FHR.

Currently, we only report a subset of the available fields. The
remaining "public" fields could be added easily enough. For now, it is
important that we capture the important ones.

--HG--
extra : rebase_source : 925d6ea04118296108327dc843323b150b87b208