I disabled Airdrop in Terminal... How to get it back?

Hi, in need of expert help here.

I followed these instructions turn disable airdrop quite a long time ago:

http://krypted.com/mac-security/disable-airdrop-in-mac-os-x-lion/

And now when I try to enable it again, nothing happens. Does anyone have a clue how to get airdrop back?

It's not even an option for the Finder sidebar anymore. I'm now running OS X El Capitan 10.11.1 on a mide-2011 iMac.

Thanks a lot in advance

Henry