Add missing case for CustomScan.
Add missing case for CustomScan.

Per KaiGai Kohei.

In passing improve formatting of some code added in commit 30d7ae3c,
because otherwise pgindent will make a mess of it.

greenplum-db/gpdb,lisakowen/gpdb,zeroae/postgres-xl,pavanvd/postgres-xl,xinzweb/gpdb,oberstet/postgres-xl,techdragon/Postgres-XL,xinzweb/gpdb,zeroae/postgres-xl,Postgres-XL/Postgres-XL,ashwinstar/gpdb,lisakowen/gpdb,yazun/postgres-xl,xinzweb/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,zeroae/postgres-xl,50wu/gpdb,Postgres-XL/Postgres-XL,oberstet/postgres-xl,Postgres-XL/Postgres-XL,pavanvd/postgres-xl,greenplum-db/gpdb,xinzweb/gpdb,techdragon/Postgres-XL,adam8157/gpdb,50wu/gpdb,ovr/postgres-xl,lisakowen/gpdb,xinzweb/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,adam8157/gpdb,techdragon/Postgres-XL,zeroae/postgres-xl,pavanvd/postgres-xl,yazun/postgres-xl,ashwinstar/gpdb,jmcatamney/gpdb,zeroae/postgres-xl,50wu/gpdb,lisakowen/gpdb,lisakowen/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,techdragon/Postgres-XL,ovr/postgres-xl,ashwinstar/gpdb,pavanvd/postgres-xl,50wu/gpdb,ashwinstar/gpdb,oberstet/postgres-xl,yazun/postgres-xl,50wu/gpdb,greenplum-db/gpdb,Postgres-XL/Postgres-XL,yazun/postgres-xl,Postgres-XL/Postgres-XL,jmcatamney/gpdb,adam8157/gpdb,ashwinstar/gpdb,lisakowen/gpdb,50wu/gpdb,greenplum-db/gpdb,ovr/postgres-xl,ashwinstar/gpdb,adam8157/gpdb,xinzweb/gpdb,jmcatamney/gpdb,adam8157/gpdb,xinzweb/gpdb,pavanvd/postgres-xl,yazun/postgres-xl,ovr/postgres-xl,jmcatamney/gpdb,techdragon/Postgres-XL,lisakowen/gpdb,xinzweb/gpdb,50wu/gpdb,oberstet/postgres-xl,adam8157/gpdb,ashwinstar/gpdb,50wu/gpdb,adam8157/gpdb,adam8157/gpdb,oberstet/postgres-xl,lisakowen/gpdb,greenplum-db/gpdb,ovr/postgres-xl