Disable WithFields logging in the ipsets resync parse loop.
Disable WithFields logging in the ipsets resync parse loop.

This speeds up the loop by a factor of 3-4x.  On my torture test, it reduced
the time from 1.2s to 350ms, which is a huge win on the critical path.

Metaswitch/calico,neiljerram/felix,Metaswitch/calico,neiljerram/felix,neiljerram/felix,neiljerram/felix