Fixing web test by handling len([]string)=0.
Fixing web test by handling len([]string)=0.

When displaying an []string (as GetShardNames() would return), api
returns '[]' instead of 'null' for empty array.

alainjobart/vitess,pivanof/vitess,rnavarro/vitess,HubSpot/vitess,pivanof/vitess,alainjobart/vitess,davygeek/vitess,alainjobart/vitess,tirsen/vitess,HubSpot/vitess,davygeek/vitess,vitessio/vitess,sougou/vitess,tirsen/vitess,dcadevil/vitess,tirsen/vitess,alainjobart/vitess,alainjobart/vitess,tinyspeck/vitess,vitessio/vitess,mattharden/vitess,dcadevil/vitess,davygeek/vitess,HubSpot/vitess,alainjobart/vitess,enisoc/vitess,mahak/vitess,rnavarro/vitess,pivanof/vitess,mahak/vitess,pivanof/vitess,davygeek/vitess,sougou/vitess,enisoc/vitess,tinyspeck/vitess,tirsen/vitess,pivanof/vitess,pivanof/vitess,davygeek/vitess,enisoc/vitess,vitessio/vitess,vitessio/vitess,HubSpot/vitess,mahak/vitess,mahak/vitess,mattharden/vitess,tirsen/vitess,mattharden/vitess,rnavarro/vitess,dcadevil/vitess,mattharden/vitess,mahak/vitess,enisoc/vitess,tirsen/vitess,sougou/vitess,dcadevil/vitess,mattharden/vitess,sougou/vitess,rnavarro/vitess,HubSpot/vitess,tirsen/vitess,HubSpot/vitess,vitessio/vitess,mattharden/vitess,vitessio/vitess,mattharden/vitess,pivanof/vitess,alainjobart/vitess,mattharden/vitess,HubSpot/vitess,rnavarro/vitess,sougou/vitess,vitessio/vitess,davygeek/vitess,sougou/vitess,mahak/vitess,pivanof/vitess,pivanof/vitess,enisoc/vitess,enisoc/vitess,dcadevil/vitess,tinyspeck/vitess,rnavarro/vitess,rnavarro/vitess,tinyspeck/vitess,sougou/vitess,mahak/vitess,mahak/vitess,alainjobart/vitess,tinyspeck/vitess,davygeek/vitess,tinyspeck/vitess,tirsen/vitess,mattharden/vitess,tirsen/vitess,sougou/vitess,rnavarro/vitess,enisoc/vitess,mattharden/vitess,HubSpot/vitess,dcadevil/vitess,rnavarro/vitess,vitessio/vitess,dcadevil/vitess,tinyspeck/vitess