pgsql: pageinspect: use index_close() for GiST index relation

pageinspect: use index_close() for GiST index relation

gist_page_items() opens its target relation with index_open(), but
closed it using relation_close() instead of index_close(). This was
harmless because index_close() and relation_close() do the exact same
work, still inconsistent with the rest of the code tree as routines
opening and closing a relation based on a relkind are expected to match,
at least in name.

Author: Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com>
Discussion: https://postgr.es/m/CAEoWx2=bL41WWcD-4Fxx-buS2Y2G5=9PjkxZbHeFMR6Uy2WNvw@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/171198ff2a57fafe0772ec9d3dfbf061cffffacd

Modified Files
--------------
contrib/pageinspect/gistfuncs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)