Avoid rare race condition in privileges.sql regression test.

We created a temp table, then switched to a new session, leaving
the old session to clean up its temp objects in background.  If that
took long enough, the eventual attempt to drop the user that owns
the temp table could fail, as exhibited today by sidewinder.
Fix by dropping the temp table explicitly when we're done with it.

It's been like this for quite some time, so back-patch to all
supported branches.

Report: https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=sidewinder&dt=2018-10-16%2014%3A45%3A00

2 files changed, 2 insertions, 0 deletions

diff --git a/src/test/regress/expected/privileges.out b/src/test/regress/expected/privileges.out
index d544fc9001e..996b4d9fd78 100644
--- a/src/test/regress/expected/privileges.out
+++ b/src/test/regress/expected/privileges.out
@@ -1093,6 +1093,7 @@ select has_column_privilege('mytable',2::int2,'select');
  
 (1 row)
 
+drop table mytable;
 -- Grant options
 SET SESSION AUTHORIZATION regressuser1;
 CREATE TABLE atest4 (a int);
diff --git a/src/test/regress/sql/privileges.sql b/src/test/regress/sql/privileges.sql
index 42af65bc7ed..27441a8b23c 100644
--- a/src/test/regress/sql/privileges.sql
+++ b/src/test/regress/sql/privileges.sql
@@ -674,6 +674,7 @@ select has_column_privilege('mytable','........pg.dropped.2........','select');
 select has_column_privilege('mytable',2::int2,'select');
 revoke select on table mytable from regressuser3;
 select has_column_privilege('mytable',2::int2,'select');
+drop table mytable;
 
 -- Grant options