Allow direct datanode sessions to grab an XID from the GTM directly.
Allow direct datanode sessions to grab an XID from the GTM directly.

Earlier we had tightened this so that all datanode sessions must get XID from
coordinators. But this creates issues for direct client connections which are
required, for example, to take a pg_dump of the datanode. So relax this a bit
and only force coordinator supplied XID for coordinator originated connections

Postgres-XL/Postgres-XL,oberstet/postgres-xl,zeroae/postgres-xl,techdragon/Postgres-XL,techdragon/Postgres-XL,pavanvd/postgres-xl,pavanvd/postgres-xl,ovr/postgres-xl,Postgres-XL/Postgres-XL,pavanvd/postgres-xl,ovr/postgres-xl,yazun/postgres-xl,ovr/postgres-xl,oberstet/postgres-xl,yazun/postgres-xl,pavanvd/postgres-xl,oberstet/postgres-xl,ovr/postgres-xl,techdragon/Postgres-XL,ovr/postgres-xl,pavanvd/postgres-xl,techdragon/Postgres-XL,yazun/postgres-xl,yazun/postgres-xl,oberstet/postgres-xl,Postgres-XL/Postgres-XL,oberstet/postgres-xl,yazun/postgres-xl,zeroae/postgres-xl,zeroae/postgres-xl,Postgres-XL/Postgres-XL,techdragon/Postgres-XL,zeroae/postgres-xl,zeroae/postgres-xl,Postgres-XL/Postgres-XL