Fix nock to 2.17.0
Fix nock to 2.17.0

2.18 seems to have [an ugly bug](https://github.com/pgte/nock/issues/402),
which causes requests to hosts that were previously mocked to time out on node
0.10.

Bug: https://phabricator.wikimedia.org/T118650

d00rman/restbase,wikimedia/mediawiki-services-restbase,gwicke/restbase,Pchelolo/restbase,milimetric/restbase,inverno/restbase,wikimedia/restbase,milimetric/restbase,inverno/restbase,cscott/restbase,cscott/restbase,eevans/restbase,gwicke/restbase,wikimedia/mediawiki-services-restbase,d00rman/restbase,wikimedia/hyperswitch,wikimedia/restbase,Pchelolo/restbase,eevans/restbase