A join that was added in commit 9b2009c4 that did not use the INNER
keyword but the existing query used it.  It was cleaner to remove the
existing INNER keyword.

Reported-by: Peter Eisentraut

Discussion: https://postgr.es/m/a1ffbfda-59d2-5732-e5fb-3df8582b6434@2ndquadrant.com

Backpatch-through: 9.5