tests: eventstest: update dict_match function and rename to partial_match
tests: eventstest: update dict_match function and rename to partial_match

The partial_match function allows for better recursive calls than
the previous dict_match, as it does not assume the element it
receives is a dictionnary. It also allows to match the content of
lists recursively.

Change-Id: I684dc94a83ce2f793570ce7e9458e74cae9c3d14
Reviewed-By: Dave Reeve <6a84ee3ae0690d4584b99406fb3076392171f50e@morganstanley.com>

quattor/aquilon,quattor/aquilon,quattor/aquilon