Fix problems related to RangeTblEntry members enrname and enrtuples.
Commit
18ce3a4ab22d2984f8540ab480979c851dae5338 failed to update
the comments in parsenodes.h for the new members, and made only
incomplete updates to src/backend/nodes
Thomas Munro, per a report from Noah Misch.
Discussion: http://postgr.es/m/
20170611062525.GA1628882@rfd.leadboat.com