pgsql: Salvage a little bit of work from a failed patch: simplify and

Log Message:
-----------
Salvage a little bit of work from a failed patch: simplify and speed up
set_rel_width(). The code had been catering for the possibility of different
varnos in the relation targetlist, but this is impossible for a base relation
(and if it were possible, putting all the widths in the same RelOptInfo would
be wrong anyway).

Modified Files:
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pgsql/src/backend/optimizer/path:
costsize.c (r1.198 -> r1.199)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/path/costsize.c?r1=1.198&r2=1.199)