discover: crashes

[akvadrako]

on armv7l with go 1.11 and latest sluez version.

dev@devpi:~$ ./go/bin/sluez discover
Adapters:
1) name="devpi" alias="devpi" address="AA:AA:AA:AA:AA:AA" discoverable=false pairable=false powered=true discovering=false
Connected devices:
watching for new bluetooth events, make sure to put device into pairing mode
panic: interface conversion: interface {} is nil, not string

goroutine 1 [running]:
github.com/vishen/sluez/bluez.(*Bluez).ConvertToDevices(0x104c020, 0x10d0150, 0x25, 0x10be3c0, 0x3, 0x4d, 0x0)
	/home/dev/go/src/github.com/vishen/sluez/bluez/device.go:88 +0x52c
github.com/vishen/sluez/cmd.glob..func4(0x3d2f00, 0x3e4b70, 0x0, 0x0, 0x0, 0x0)
	/home/dev/go/src/github.com/vishen/sluez/cmd/discover.go:71 +0x6dc
github.com/vishen/sluez/vendor/github.com/spf13/cobra.(*Command).execute(0x3d2f00, 0x3e4b70, 0x0, 0x0, 0x3d2f00, 0x3e4b70)
	/home/dev/go/src/github.com/vishen/sluez/vendor/github.com/spf13/cobra/command.go:762 +0x364
github.com/vishen/sluez/vendor/github.com/spf13/cobra.(*Command).ExecuteC(0x3d3290, 0x16764, 0x1066030, 0x0)
	/home/dev/go/src/github.com/vishen/sluez/vendor/github.com/spf13/cobra/command.go:852 +0x210
github.com/vishen/sluez/vendor/github.com/spf13/cobra.(*Command).Execute(0x3d3290, 0x1066030, 0x0)
	/home/dev/go/src/github.com/vishen/sluez/vendor/github.com/spf13/cobra/command.go:800 +0x1c
github.com/vishen/sluez/cmd.Execute()
	/home/dev/go/src/github.com/vishen/sluez/cmd/root.go:33 +0x20
main.main()
	/home/dev/go/src/github.com/vishen/sluez/main.go:20 +0x14