influxdb: panic: runtime error: invalid memory address or nil pointer dereference (PointsWriter)

Hi,

I had a crash of the InfluxDB process (1.3.4) on ubuntu 16.04 on amd64

Installed version: Sep 4 16:38:09 nuc1 influxd[19775]: [I] 2017-09-04T14:38:09Z InfluxDB starting, version 1.3.4, branch HEAD, commit 0c54d8fc744220b8dc70f2987e04e78fec951285

Process was restarted. Only happend once till now.

Sep  4 16:38:09 nuc1 influxd[1670]: panic: runtime error: invalid memory address or nil pointer dereference
Sep  4 16:38:09 nuc1 influxd[1670]: [signal SIGSEGV: segmentation violation code=0x1 addr=0xb8 pc=0x86f9a3]
Sep  4 16:38:09 nuc1 influxd[1670]: goroutine 1783 [running]:
Sep  4 16:38:09 nuc1 influxd[1670]: github.com/influxdata/influxdb/coordinator.(*PointsWriter).MapShards(0xc42005f700, 0xc4205c7c68, 0x8, 0x
c44395ff40, 0x4ed23b430)
Sep  4 16:38:09 nuc1 influxd[1670]: #011/root/go/src/github.com/influxdata/influxdb/coordinator/points_writer.go:210 +0x1d3
Sep  4 16:38:09 nuc1 influxd[1670]: github.com/influxdata/influxdb/coordinator.(*PointsWriter).WritePointsPrivileged(0xc42005f700, 0xb8b250,
 0x8, 0xc42016d338, 0x7, 0x0, 0xc439e1e000, 0x3e8, 0x3e8, 0x0, ...)
Sep  4 16:38:09 nuc1 influxd[1670]: #011/root/go/src/github.com/influxdata/influxdb/coordinator/points_writer.go:305 +0x13c
Sep  4 16:38:09 nuc1 influxd[1670]: github.com/influxdata/influxdb/services/collectd.(*Service).writePoints(0xc4200c2600)
Sep  4 16:38:09 nuc1 influxd[1670]: #011/root/go/src/github.com/influxdata/influxdb/services/collectd/service.go:377 +0x32d
Sep  4 16:38:09 nuc1 influxd[1670]: github.com/influxdata/influxdb/services/collectd.(*Service).Open.func3(0xc4200c2600)
Sep  4 16:38:09 nuc1 influxd[1670]: #011/root/go/src/github.com/influxdata/influxdb/services/collectd/service.go:207 +0x57
Sep  4 16:38:09 nuc1 influxd[1670]: created by github.com/influxdata/influxdb/services/collectd.(*Service).Open
Sep  4 16:38:09 nuc1 influxd[1670]: #011/root/go/src/github.com/influxdata/influxdb/services/collectd/service.go:207 +0x78d