A patch for Bug#11765297 (58251 - archive_plugin and blackhole_plugin

fails when running with ps-protocol).

The problem was that when running in --ps-protocol mode mysqltest.cc
didn't close created prepared statements. So, the plugins could not be
unistalled because there was a prepared statement using them.

A fix is to add a dummy statement that forces mysqltest.cc to close
the last prepared statement (which uses a plugin-defined table).

mysql-test/r/archive_plugin.result

@@ -10,6 +10,9 @@ UNINSTALL PLUGIN archive;
 INSTALL PLUGIN archive SONAME 'ha_archive.so';
 CREATE TABLE t1(a int) ENGINE=ARCHIVE;
 DROP TABLE t1;
+SELECT 1;
+1
+1
 UNINSTALL PLUGIN archive;
 UNINSTALL PLUGIN archive;
 ERROR 42000: PLUGIN archive does not exist

mysql-test/r/blackhole_plugin.result

@@ -10,6 +10,9 @@ UNINSTALL PLUGIN blackhole;
 INSTALL PLUGIN blackhole SONAME 'ha_blackhole.so';
 CREATE TABLE t1(a int) ENGINE=BLACKHOLE;
 DROP TABLE t1;
+SELECT 1;
+1
+1
 UNINSTALL PLUGIN blackhole;
 UNINSTALL PLUGIN blackhole;
 ERROR 42000: PLUGIN blackhole does not exist

mysql-test/t/archive_plugin.test

@@ -20,6 +20,14 @@ CREATE TABLE t1(a int) ENGINE=ARCHIVE;
 
 DROP TABLE t1;
 
+# This dummy statement is required for --ps-protocol mode.
+# The thing is that last prepared statement is "cached" in mysqltest.cc
+# (unless "reconnect" is enabled, and that's not the case here).
+# This statement forces mysqltest.cc to close prepared "DROP TABLE t1".
+# Otherwise, the plugin can not be uninstalled because there is an active
+# prepared statement using it.
+SELECT 1;
+
 UNINSTALL PLUGIN archive;
 
 --error ER_SP_DOES_NOT_EXIST 

mysql-test/t/blackhole_plugin.test

@@ -20,6 +20,14 @@ CREATE TABLE t1(a int) ENGINE=BLACKHOLE;
 
 DROP TABLE t1;
 
+# This dummy statement is required for --ps-protocol mode.
+# The thing is that last prepared statement is "cached" in mysqltest.cc
+# (unless "reconnect" is enabled, and that's not the case here).
+# This statement forces mysqltest.cc to close prepared "DROP TABLE t1".
+# Otherwise, the plugin can not be uninstalled because there is an active
+# prepared statement using it.
+SELECT 1;
+
 UNINSTALL PLUGIN blackhole;
 --error ER_SP_DOES_NOT_EXIST
 UNINSTALL PLUGIN blackhole;