Fix legacy record dropdown repopulation

Fix legacy record dropdown repopulation

Whenever the staff client OPAC would refresh (for instance, when
editing the MFHD record), the legacy record dropdown selector in
the serial control distribution editor would lose track of the
associated records. This bug was traced back to some funny
interactions with the global mfhdDetails variable, and the best
solution was to not rely on the event reading the global at all,
but rather to pass mfhdDetails into the event handler instead.

This commit corrects the issue in both the TPAC and the JSPAC,
and also fixes a small display issue when using TPAC (entryNum
must be an integer, not a string, as it gets incremented before
it is displayed in the editor).

Signed-off-by: Dan Wells <dbw2@calvin.edu>