bugfix: mmjsonparse did not build with json-c < 0.10

This was a regression introduced some time in the past in order to
support API changes in json-c. Now we check for the version and use
proper code.

Conflicts:

	ChangeLog
begin new 8.4 stable branch
Merge branch 'v7-stable' of git+ssh://git.adiscon.com/git/rsyslog into v7-stable
Merge branch 'v7-stable' into v8-stable
kick off 8.5 branch