Fixed possible segfault in swoole_table

[bixuehujin]

The memory_size in swTable_create should be:

size_t memory_size = (row_num * row_memory_size) + (table->size * sizeof(swTableRow *))  + sizeof(swMemoryPool) + sizeof(swFixedPool) + ((row_num - table->size) * sizeof(swFixedPool_slice));

otherwise, swFixedPool_init() may override not allocated memory and cause segfault.