Fix inappropriate error messages for Hot Standby misconfiguration errors.
Fix inappropriate error messages for Hot Standby misconfiguration errors.

Give the correct name of the GUC parameter being complained of.
Also, emit a more suitable SQLSTATE (INVALID_PARAMETER_VALUE,
not the default INTERNAL_ERROR).

Gurjeet Singh, errcode adjustment by me

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