Ensure WAL is closed when closing engine
Ensure WAL is closed when closing engine

If a database is dropped, the WAL maintenance goroutines could still
kick in an fail becase the DB dirs are gone.

jipperinbham/influxdb,jgeiger/influxdb,jonseymour/influxdb,jgeiger/influxdb,jgeiger/influxdb,CVTJNII/influxdb-tjnii,mnuessler/influxdb,daachi/influxdb,pablolmiranda/influxdb,benbjohnson/influxdb,vladlopes/influxdb,Mindera/influxdb,li-ang/influxdb,mvadu/influxdb,mark-rushakoff/influxdb,pablolmiranda/influxdb,jonseymour/influxdb,pablolmiranda/influxdb,mark-rushakoff/influxdb,apigee/influxdb,influxdb/influxdb,archsaber/influxdb,arussellsaw/influxdb,chenziliang/influxdb,samaitra/influxdb,runner-mei/influxdb,sudabon/influxdb,jonseymour/influxdb,mvadu/influxdb,n1tr0g/influxdb,daachi/influxdb,vladlopes/influxdb,li-ang/influxdb,m4ce/influxdb,daachi/influxdb,influxdb/influxdb,n1tr0g/influxdb,joaopedrotaveira/influxdb,Mindera/influxdb,linearb/influxdb,nooproblem/influxdb,jipperinbham/influxdb,influxdb/influxdb,nooproblem/influxdb,linearb/influxdb,nickrobinson/influxdb,arussellsaw/influxdb,mnuessler/influxdb,m4ce/influxdb,jgeiger/influxdb,daachi/influxdb,lgpeterson/influxdb,mvadu/influxdb,otoolep/influxdb,Mindera/influxdb,n1tr0g/influxdb,sudabon/influxdb,lgpeterson/influxdb,jonseymour/influxdb,joaopedrotaveira/influxdb,apigee/influxdb,CVTJNII/influxdb-tjnii,samaitra/influxdb,mark-rushakoff/influxdb,otoolep/influxdb,joaopedrotaveira/influxdb,pkittenis/influxdb,arussellsaw/influxdb,m4ce/influxdb,jgeiger/influxdb,benbjohnson/influxdb,arussellsaw/influxdb,nickrobinson/influxdb,influxdb/influxdb,archsaber/influxdb,linearb/influxdb,jipperinbham/influxdb,nooproblem/influxdb,mark-rushakoff/influxdb,Mindera/influxdb,samaitra/influxdb,nickrobinson/influxdb,benbjohnson/influxdb,linearb/influxdb,jonseymour/influxdb,m4ce/influxdb,influxdb/influxdb,runner-mei/influxdb,daachi/influxdb,n1tr0g/influxdb,pkittenis/influxdb,runner-mei/influxdb,otoolep/influxdb,runner-mei/influxdb,CVTJNII/influxdb-tjnii,lgpeterson/influxdb,bluebreezecf/influxdb,apigee/influxdb,pkittenis/influxdb,linearb/influxdb,m4ce/influxdb,mvadu/influxdb,apigee/influxdb,pablolmiranda/influxdb,mnuessler/influxdb,influxdb/influxdb,lgpeterson/influxdb,joaopedrotaveira/influxdb,sudabon/influxdb,arussellsaw/influxdb,jipperinbham/influxdb,nooproblem/influxdb,CVTJNII/influxdb-tjnii,sudabon/influxdb,chenziliang/influxdb,archsaber/influxdb,mnuessler/influxdb,apigee/influxdb,jgeiger/influxdb,mnuessler/influxdb,sudabon/influxdb,nickrobinson/influxdb,jipperinbham/influxdb,influxdata/influxdb,chenziliang/influxdb,n1tr0g/influxdb,Mindera/influxdb,pkittenis/influxdb,otoolep/influxdb,samaitra/influxdb,vladlopes/influxdb,nickrobinson/influxdb,sudabon/influxdb,pablolmiranda/influxdb,daachi/influxdb,benbjohnson/influxdb,chenziliang/influxdb,lgpeterson/influxdb,bluebreezecf/influxdb,samaitra/influxdb,otoolep/influxdb,influxdata/influxdb,Mindera/influxdb,bluebreezecf/influxdb,m4ce/influxdb,otoolep/influxdb,mvadu/influxdb,jonseymour/influxdb,mark-rushakoff/influxdb,arussellsaw/influxdb,bluebreezecf/influxdb,apigee/influxdb,n1tr0g/influxdb,CVTJNII/influxdb-tjnii,jipperinbham/influxdb,pkittenis/influxdb,archsaber/influxdb,joaopedrotaveira/influxdb,mark-rushakoff/influxdb,samaitra/influxdb,vladlopes/influxdb,bluebreezecf/influxdb,mvadu/influxdb,pkittenis/influxdb,mnuessler/influxdb,nooproblem/influxdb,CVTJNII/influxdb-tjnii