Bump src/gnatsd

Bump apcera/gnatsd:
  Derek Collison:
     Merge pull request #44 from fraenkel/stale_reconnect ( Travis Failed: https://travis-ci.org/apcera/gnatsd/builds/35358914 )
     Merge pull request #47 from fraenkel/remove_race ( Travis Success: https://travis-ci.org/apcera/gnatsd/builds/35358657 )
     Merge pull request #46 from fraenkel/self_reference ( Travis Success: https://travis-ci.org/apcera/gnatsd/builds/35358488 )
     Merge pull request #45 from fraenkel/varz ( Travis Failed: https://travis-ci.org/apcera/gnatsd/builds/35358319 )
  Michael Fraenkel:
     Prevent duplicate routes properly ( Travis Unknown )
     Check port when removing self referenced routes ( Travis Unknown )
     Add routes and remotes to varz ( Travis Unknown )