Cleanup testcases

- Add  missing drop(s)
 - Reset changed variables

NOTE! These kind of problems are easily found with --check-testcases options to mysql-test-run.pl 


mysql-test/extra/rpl_tests/rpl_insert_id_pk.test:
  Add missing drop table
mysql-test/extra/rpl_tests/rpl_loaddata.test:
  Add missing drop table
mysql-test/extra/rpl_tests/rpl_log.test:
  Tables where only dropped on slave, switch to master connection before dropping them
mysql-test/extra/rpl_tests/rpl_multi_update3.test:
  Add missing drop table
mysql-test/extra/rpl_tests/rpl_row_sp006.test:
  Add missing drop database
mysql-test/include/check-testcase.test:
  Add option "--skip-lock-tables" when dumping tables, as noone else is using the tables anyway
mysql-test/r/ndb_cache_multi.result:
  Reset query_cache_size after test on both master and "second" master mysqld
mysql-test/r/partition.result:
  Add missing drop procedure
mysql-test/r/rpl_drop_db.result:
  Add missing drop table
mysql-test/r/rpl_multi_update3.result:
  Add missing drop table
mysql-test/r/rpl_ndb_multi_update3.result:
  Add missing drop table
mysql-test/r/rpl_ndb_sp006.result:
  Add missing drop database
mysql-test/r/rpl_stm_no_op.result:
  Add missing drop table
mysql-test/r/rpl_variables.result:
  Reset slave_net_timeout to it's default value after test
mysql-test/t/ndb_cache_multi.test:
  Reset query_cahche_size after test
mysql-test/t/partition.test:
  Add missing drop procedure
mysql-test/t/rpl_drop_db.test:
  Add missing drop table
mysql-test/t/rpl_stm_no_op.test:
  Add missing drop table
mysql-test/t/rpl_variables.test:
  Reset slave_net_timeout to it's default value after test

mysql-test/extra/rpl_tests/rpl_loaddata.test

@@ -152,5 +152,5 @@ wait_for_slave_to_stop;
 drop table t2;
 connection master;
 drop table t2;
-
+drop table t1;
 # End of 4.1 tests