Handles trailing empty line at connectedInterfaces

EOS 4.14.1 sends and empty trailing line out the 'show interfaces status connected' in *text* mode. This was causing an error int the function connectedInterfaces when doing x.split()[ 0 ] : x was nil.
The added "if x" makes the check.
I have not tested other commands outputs, the trailing empty line (\n\n) might occur with other commands
Thanks for looking into this!

I am a bit concerned though - I think your changes will only return the "FIRST connected interface" (whereas the original code was intended to return "ALL connected interfaces"). I hope I am not missing something here.

How about:

return [ x.split()[ 0 ] for x in output if x.split() ]

?
I believe this would do the trick