Fix resource leak in initdb -X option
Fix resource leak in initdb -X option

When creating the symlink for the xlog directory, free the string
which stores the link location.  Not really an issue but it doesn't
hurt to be good about this- prior cleanups have fixed similar
issues.

Leak found by the Coverity scanner.

Not back-patching as I don't see it being worth the code churn.

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