LP #1092179 FlattenerGrid Filter dialog lead to clobbering grid's base query

LP #1092179 FlattenerGrid Filter dialog lead to clobbering grid's base query

You could see this in the Simplified Hold Pull List interface.  Using
the filter dialog would refresh the grid and populate it with rows
corresponding to your filters, but it would throw away your setting from
the context org dropdown (labeled "Show the pull list for..." there).

FlattenerGrid had a broken mechanism for trying to nicely mix a user's
input from things like context org dropdowns with whatever they put into
the filter dialog, and now that mechanism has been fixed.

This also means a tiny change to the User Event Log interface to react
to the slight change in FlattenerGrid's API.

Signed-off-by: Lebbeous Fogle-Weekley <lebbeous@esilibrary.com>
Signed-off-by: Ben Shum <bshum@biblio.org>