LP#1713764: fix 'Retrieve Patron' action from webstaff pull list

LP#1713764: fix 'Retrieve Patron' action from webstaff pull list

This patch fixes a regression wherein the Retrieve Patron action
didn't work on the pull list grid by ensuring that the user value
would get fleshed.

To test
-------
[1] Go to the pull list in the web staff client and attempt the
    'Retrieve Patron' action. Note that nothing happens.
[2] Apply the patch and repeat step 1; this time, a new window
    should be opened with the patron record.

Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>