status-history panics with badly formatted names

$ juju status-history wqelgnweglewgnwglnegwlw
panic: "wqelgnweglewgnwglnegwlw" is not a valid unit name

goroutine 1 [running]:
panic(0x19d0c60, 0xc82049dad0)
 /home/nate/go/src/runtime/panic.go:481 +0x3e6
github.com/juju/names.NewUnitTag(0x7ffc9942f0aa, 0xd, 0x0, 0x0)
 /home/nate/src/github.com/juju/names/unit.go:29 +0x1ad
github.com/juju/juju/cmd/juju/status.(*statusHistoryCommand).Run(0xc8201501e0, 0xc820328780, 0x0, 0x0)
 /home/nate/src/github.com/juju/juju/cmd/juju/status/history.go:138 +0x285
github.com/juju/juju/cmd/modelcmd.(*modelCommandWrapper).Run(0xc820422840, 0xc820328780, 0x0, 0x0)
 /home/nate/src/github.com/juju/juju/cmd/modelcmd/modelcommand.go:273 +0x4f
github.com/juju/juju/cmd/modelcmd.(*baseCommandWrapper).Run(0xc820327480, 0xc820328780, 0x0, 0x0)
 /home/nate/src/github.com/juju/juju/cmd/modelcmd/base.go:205 +0xd4
github.com/juju/cmd.(*SuperCommand).Run(0xc82018bd00, 0xc820328780, 0x0, 0x0)
 /home/nate/src/github.com/juju/cmd/supercommand.go:446 +0x688
github.com/juju/cmd.Main(0x7f9d83405678, 0xc82018bd00, 0xc820328780, 0xc82000a370, 0x2, 0x2, 0x4acdca)
 /home/nate/src/github.com/juju/cmd/cmd.go:280 +0x2f0
github.com/juju/juju/cmd/juju/commands.main.Run(0x2a857c8, 0xc82000a360, 0x3, 0x3, 0xc82021de20)
 /home/nate/src/github.com/juju/juju/cmd/juju/commands/main.go:148 +0x5bb
github.com/juju/juju/cmd/juju/commands.Main(0xc82000a360, 0x3, 0x3, 0xc820000180)
 /home/nate/src/github.com/juju/juju/cmd/juju/commands/main.go:113 +0x48
main.main()
 /home/nate/src/github.com/juju/juju/cmd/juju/main.go:27 +0x3b