LP#1549505: Query literal interpolation casts incorrectly

LP#1549505: Query literal interpolation casts incorrectly

We need to be sure that all query values are of the same type in the same
columns because PLPGSQL functions are compiled and cached.  In this case,
the core query of the in-db search cannot have its shape change.  This
committ assures that browse and search uses of the SP provide core queries
that match on their SELECT lists.  Of particular importance is the type
of the "rel" output column, which was variously float8 or numeric, depending
on whether the search contained any terms (a "search") or not (a browse
link).

Signed-off-by: Mike Rylander <mrylander@gmail.com>