Runtime error due to no PowerOutageFlags in NetIDM meters about rtlamr-collect

[bemasher]

The commit message for the fix is misleading. binary.BigEndian.Uint64 will fail on index out of bounds because the byte slice isn't guaranteed to be 8 bytes long when idm.Outage flags is empty.

The new code will always succeed even if idm.Outage contains no data.

[fcovatti]

29.10.19 22:11:35 (-0300)  panic: runtime error: index out of range
29.10.19 22:11:35 (-0300)  goroutine 1 [running]:
29.10.19 22:11:35 (-0300)  encoding/binary.bigEndian.Uint64(...)
29.10.19 22:11:35 (-0300)  /usr/local/go/src/encoding/binary/binary.go:124
29.10.19 22:11:35 (-0300)  main.IDM.AddPoints(0x1074aa0, 0x8, 0x19dd4b4, 0x5f03ab, 0x1068640, 0x1b, 0x1c, 0x0, 0x0, 0x0, ...)
29.10.19 22:11:35 (-0300)  /go/pkg/mod/github.com/bemasher/rtlamr-collect/main.go:78 +0x908
29.10.19 22:11:35 (-0300)  main.main()
29.10.19 22:11:35 (-0300)  /go/pkg/mod/github.com/bemasher/rtlamr-collect/main.go:426 +0x5fc

[fcovatti]

Thanks for the Update. Tested and it worked after the change!