mysql57: follow init_sql_alloc() API change
mysql57: follow init_sql_alloc() API change

mroonga/mroonga,mroonga/mroonga,mroonga/mroonga,yoku0825/mroonga,mroonga/mroonga,naoa/mroonga,yoku0825/mroonga,naoa/mroonga,naoa/mroonga,yoku0825/mroonga,yoku0825/mroonga,naoa/mroonga,naoa/mroonga,naoa/mroonga,yoku0825/mroonga,yoku0825/mroonga