Bug#51851: Server with SBR locks mutex twice on

LOAD DATA into partitioned MyISAM table

Problem was that both partitioning and myisam
used the same table_share->mutex for different protections
(auto inc and repair).

Solved by adding a specific mutex for the partitioning
auto_increment.

Also adding destroying the ha_data structure in
free_table_share (which is to be propagated
into 5.5).

This is a 5.1 ONLY patch, already fixed in 5.5+.

mysql-test/r/partition_binlog_stmt.result

@@ -0,0 +1,13 @@
+DROP TABLE IF EXISTS t1;
+#
+# Bug#51851: Server with SBR locks mutex twice on LOAD DATA into
+#            partitioned MyISAM table
+CREATE TABLE t1
+(id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
+name TINYBLOB NOT NULL,
+modified TIMESTAMP DEFAULT '0000-00-00 00:00:00',
+INDEX namelocs (name(255))) ENGINE = MyISAM
+PARTITION BY HASH(id) PARTITIONS 2;
+LOAD DATA LOCAL INFILE 'init_file.txt'
+INTO TABLE t1 (name);
+DROP TABLE t1;

mysql-test/t/partition_binlog_stmt.test

@@ -0,0 +1,26 @@
+--source include/have_partition.inc
+--source include/have_binlog_format_statement.inc
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+--enable_warnings
+
+--echo #
+--echo # Bug#51851: Server with SBR locks mutex twice on LOAD DATA into
+--echo #            partitioned MyISAM table
+--write_file init_file.txt
+abcd
+EOF
+
+CREATE TABLE t1
+(id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
+ name TINYBLOB NOT NULL,
+ modified TIMESTAMP DEFAULT '0000-00-00 00:00:00',
+ INDEX namelocs (name(255))) ENGINE = MyISAM
+PARTITION BY HASH(id) PARTITIONS 2;
+
+LOAD DATA LOCAL INFILE 'init_file.txt'
+INTO TABLE t1 (name);
+
+--remove_file init_file.txt
+DROP TABLE t1;