Fix bug in WAL_DEBUG.
Fix bug in WAL_DEBUG.

The record header was not copied correctly to the buffer that was passed
to the rm_desc function. Broken by my rm_desc signature refactoring patch.

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