ENG-4680 (#873) Revert change for adding postgres log directory

Summary: https://phabricator.dev.yugabyte.com/D6183 fails Jenkins tests. Reverting this change.

Test Plan:
Tests succeed:
mvn test -Dtest=org.yb.pgsql.TestPgDelete
mvn test

Reviewers: mihnea

Reviewed By: mihnea

Differential Revision: https://phabricator.dev.yugabyte.com/D6214

src/yb/yql/pgwrapper/pg_wrapper.cc

@@ -86,9 +86,6 @@ Status PgWrapper::Start() {
     "-D", conf_.data_dir,
     "-p", std::to_string(conf_.pg_port),
     "-h", conf_.listen_addresses,
-    "-c", "logging_collector=on",
-    // FLAGS_log_dir should already be set by tserver during startup.
-    "-c", "log_directory=" + FLAGS_log_dir,
     // Disable listening on a UNIX domain socket
     "-k", ""
   };