SPY-122: Change groupID from spy to net.spy

This changeset ensures that compatibility with maven central
is achieved and can be published there too.

Change-Id: I030f0741a8ccd0bf6e96b3f323b366c152274807
Reviewed-on: http://review.couchbase.org/26181
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Reviewed-by: Matt Ingenthron <matt@couchbase.com>