Avoid recovery log messages during initdb
Avoid recovery log messages during initdb

Initdb outputs:
```
creating template1 database in data-master/base/1 ... 2019-10-15 17:32:43.566646 CST,,,p73904,th345056704,,,,0,,,seg-10000,,,,,"LOG","00000","end of transaction log location is 0/4000098",,,,,,,,"StartupXLOG","xlog.c",7417,
2019-10-15 17:32:43.567223 CST,,,p73904,th345056704,,,,0,,,seg-10000,,,,,"LOG","00000","latest completed transaction id is 4294967295 and next transaction id is 3",,,,,,,,"StartupXLOG","xlog.c",7705,
2019-10-15 17:32:43.567528 CST,,,p73904,th345056704,,,,0,,,seg-10000,,,,,"LOG","00000","database system is ready",,,,,,,,"StartupXLOG","xlog.c",7729,
ok
initializing pg_authid ... 2019-10-15 17:32:45.008956 CST,,,p73906,th83031488,,,,0,,,seg-10000,,,,,"LOG","00000","end of transaction log location is 0/40101D8",,,,,,,,"StartupXLOG","xlog.c",7417,
2019-10-15 17:32:45.009424 CST,,,p73906,th83031488,,,,0,,,seg-10000,,,,,"LOG","00000","latest completed transaction id is 4294967295 and next transaction id is 3",,,,,,,,"StartupXLOG","xlog.c",7705,
2019-10-15 17:32:45.010083 CST,,,p73906,th83031488,,,,0,,,seg-10000,,,,,"LOG","00000","database system is ready",,,,,,,,"StartupXLOG","xlog.c",7729,
ok
```

These messages are helpful during crash recovery but noise for
initdb. Hence, avoid them for initdb. With the change initdb output
looks cleaner
```
creating template1 database in data-master/base/1 ... ok
initializing pg_authid ... ok
initializing dependencies ... ok
creating system views ... ok
loading system objects' descriptions ... ok
creating conversions ... ok
```

Reported-by: Yandong Yao <512a570991a898f2c8fe450ab195cc3c5805fd28@pivotal.io>

Reviewed-by: Yandong Yao <512a570991a898f2c8fe450ab195cc3c5805fd28@pivotal.io>
Reviewed-by: Jimmy Yih <9b5ecfe15c9cd044f4ab483a287130e4bc266a44@pivotal.io>

xinzweb/gpdb,xinzweb/gpdb,50wu/gpdb,lisakowen/gpdb,lisakowen/gpdb,lisakowen/gpdb,50wu/gpdb,xinzweb/gpdb,50wu/gpdb,jmcatamney/gpdb,adam8157/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,lisakowen/gpdb,jmcatamney/gpdb,xinzweb/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,lisakowen/gpdb,ashwinstar/gpdb,lisakowen/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,adam8157/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,xinzweb/gpdb,xinzweb/gpdb,adam8157/gpdb,50wu/gpdb,50wu/gpdb,adam8157/gpdb,lisakowen/gpdb,50wu/gpdb,adam8157/gpdb,50wu/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,lisakowen/gpdb,greenplum-db/gpdb,xinzweb/gpdb,50wu/gpdb,adam8157/gpdb,greenplum-db/gpdb,adam8157/gpdb,adam8157/gpdb,ashwinstar/gpdb,xinzweb/gpdb,ashwinstar/gpdb