Leak-fix in FnCallRegExtract().

One of its premature returns neglected to free the arrayname.
remove export_zenoss constraint
Fix package_list_update_ifelapsed having no effect on "apt-get update"

Redmine #3981, #5339.

It is documented as having the described effect, but does not.

The timestamp for the last update is now maintained by a timestamp
file, /var/cfengine/state/software_update_timestamp_<manager>, where
<manager> is the package executable that is being used for the current
promise.
Ideally it should be integrated with the database, but we want the low
risk solution right now, and we plan to replace this code anyway.
tests/acceptance/01_vars/02_functions/staging/maparray.cf: minor changes, still in staging
Merge pull request #1645 from maciejmrowiec/master

remove export_zenoss constraint (codename: MongoDBectomy)
Merge pull request #1644 from ediosyncratic/leak-fix

Leak-fix in FnCallRegExtract().