Remove sync.Pool from wal UnmarshalBinary
Remove sync.Pool from wal UnmarshalBinary

When loading many shards concurrently they block trying to
acquire a write lock in the sync pool adding a new source of
contention.  Since this code flow always needs to allocate a
buffer it's not really buying us much.

jgeiger/influxdb,runner-mei/influxdb,apigee/influxdb,mark-rushakoff/influxdb,jgeiger/influxdb,influxdb/influxdb,nooproblem/influxdb,benbjohnson/influxdb,runner-mei/influxdb,nooproblem/influxdb,jipperinbham/influxdb,jipperinbham/influxdb,apigee/influxdb,nooproblem/influxdb,chenziliang/influxdb,mark-rushakoff/influxdb,benbjohnson/influxdb,arussellsaw/influxdb,vladlopes/influxdb,jgeiger/influxdb,otoolep/influxdb,apigee/influxdb,daachi/influxdb,mnuessler/influxdb,mark-rushakoff/influxdb,vladlopes/influxdb,otoolep/influxdb,chenziliang/influxdb,influxdb/influxdb,benbjohnson/influxdb,joaopedrotaveira/influxdb,daachi/influxdb,linearb/influxdb,mnuessler/influxdb,arussellsaw/influxdb,jipperinbham/influxdb,otoolep/influxdb,linearb/influxdb,jipperinbham/influxdb,archsaber/influxdb,influxdata/influxdb,vladlopes/influxdb,joaopedrotaveira/influxdb,jgeiger/influxdb,arussellsaw/influxdb,mvadu/influxdb,influxdb/influxdb,archsaber/influxdb,nooproblem/influxdb,mark-rushakoff/influxdb,joaopedrotaveira/influxdb,runner-mei/influxdb,jipperinbham/influxdb,mnuessler/influxdb,arussellsaw/influxdb,linearb/influxdb,mvadu/influxdb,daachi/influxdb,chenziliang/influxdb,pkittenis/influxdb,li-ang/influxdb,daachi/influxdb,mark-rushakoff/influxdb,otoolep/influxdb,apigee/influxdb,mnuessler/influxdb,vladlopes/influxdb,mvadu/influxdb,otoolep/influxdb,apigee/influxdb,mvadu/influxdb,arussellsaw/influxdb,daachi/influxdb,joaopedrotaveira/influxdb,linearb/influxdb,joaopedrotaveira/influxdb,pkittenis/influxdb,apigee/influxdb,otoolep/influxdb,influxdb/influxdb,li-ang/influxdb,pkittenis/influxdb,jgeiger/influxdb,mark-rushakoff/influxdb,influxdb/influxdb,arussellsaw/influxdb,mvadu/influxdb,influxdata/influxdb,benbjohnson/influxdb,pkittenis/influxdb,influxdb/influxdb,nooproblem/influxdb,pkittenis/influxdb,jgeiger/influxdb,chenziliang/influxdb,archsaber/influxdb,jipperinbham/influxdb,daachi/influxdb,linearb/influxdb,mnuessler/influxdb,mnuessler/influxdb,archsaber/influxdb,mvadu/influxdb,runner-mei/influxdb,pkittenis/influxdb