Bug#11766249 bug#59316: PARTITIONING AND INDEX_MERGE MEMORY LEAK

When executing row-ordered-retrieval index merge,
the handler was cloned, but it used the wrong
memory root, so instead of allocating memory
on the thread/query's mem_root, it used the table's
mem_root, resulting in non released memory in the
table object, and was not freed until the table was
closed.

Solution was to ensure that memory used during cloning
of a handler was allocated from the correct memory root.

This was implemented by fixing handler::clone() to also
take a name argument, so it can be used with partitioning.
And in ha_partition only allocate the ha_partition's ref, and
call the original ha_partition partitions clone() and set at cloned
partitions.

Fix of .bzrignore on Windows with VS 2010

sql/handler.cc

@@ -2037,9 +2037,9 @@ int ha_delete_table(THD *thd, handlerton *table_type, const char *path,
 /****************************************************************************
 ** General handler functions
 ****************************************************************************/
-handler *handler::clone(MEM_ROOT *mem_root)
+handler *handler::clone(const char *name, MEM_ROOT *mem_root)
 {
-  handler *new_handler= get_new_handler(table->s, mem_root, table->s->db_type());
+  handler *new_handler= get_new_handler(table->s, mem_root, ht);
   /*
     Allocate handler->ref here because otherwise ha_open will allocate it
     on this->table->mem_root and we will not be able to reclaim that memory 
@@ -2048,7 +2048,7 @@ handler *handler::clone(MEM_ROOT *mem_root)
   if (!(new_handler->ref= (uchar*) alloc_root(mem_root, ALIGN_SIZE(ref_length)*2)))
     return NULL;
   if (new_handler && !new_handler->ha_open(table,
-                                           table->s->normalized_path.str,
+                                           name,
                                            table->db_stat,
                                            HA_OPEN_IGNORE_IF_LOCKED))
     return new_handler;