Refactoring shard_conn.multiGo code.
Refactoring shard_conn.multiGo code.

To limit code duplication, and add an optimization to not
create go routines for single calls. Not using channels for
results either.

enisoc/vitess,AndyDiamondstein/vitess,tinyspeck/vitess,applift/vitess,sougou/vitess,mahak/vitess,pivanof/vitess,applift/vitess,alainjobart/vitess,tinyspeck/vitess,aaijazi/vitess,tinyspeck/vitess,dumbunny/vitess,mattharden/vitess,alainjobart/vitess,mapbased/vitess,mattharden/vitess,mattharden/vitess,mapbased/vitess,tinyspeck/vitess,erzel/vitess,applift/vitess,HubSpot/vitess,davygeek/vitess,mattharden/vitess,mattharden/vitess,sougou/vitess,tirsen/vitess,alainjobart/vitess,dumbunny/vitess,aaijazi/vitess,HubSpot/vitess,aaijazi/vitess,tirsen/vitess,vitessio/vitess,alainjobart/vitess,dcadevil/vitess,erzel/vitess,mahak/vitess,AndyDiamondstein/vitess,erzel/vitess,rnavarro/vitess,tirsen/vitess,applift/vitess,pivanof/vitess,tirsen/vitess,erzel/vitess,HubSpot/vitess,sougou/vitess,davygeek/vitess,erzel/vitess,applift/vitess,tirsen/vitess,aaijazi/vitess,AndyDiamondstein/vitess,erzel/vitess,AndyDiamondstein/vitess,tirsen/vitess,AndyDiamondstein/vitess,sougou/vitess,mahak/vitess,tinyspeck/vitess,alainjobart/vitess,dcadevil/vitess,erzel/vitess,mahak/vitess,erzel/vitess,AndyDiamondstein/vitess,tinyspeck/vitess,erzel/vitess,rnavarro/vitess,tirsen/vitess,mattharden/vitess,dcadevil/vitess,enisoc/vitess,pivanof/vitess,mattharden/vitess,rnavarro/vitess,AndyDiamondstein/vitess,applift/vitess,pivanof/vitess,HubSpot/vitess,mapbased/vitess,mapbased/vitess,mapbased/vitess,enisoc/vitess,applift/vitess,mapbased/vitess,sougou/vitess,pivanof/vitess,vitessio/vitess,applift/vitess,enisoc/vitess,davygeek/vitess,tirsen/vitess,mapbased/vitess,aaijazi/vitess,dcadevil/vitess,mapbased/vitess,alainjobart/vitess,dumbunny/vitess,alainjobart/vitess,mahak/vitess,erzel/vitess,mattharden/vitess,mahak/vitess,aaijazi/vitess,mahak/vitess,vitessio/vitess,vitessio/vitess,HubSpot/vitess,dcadevil/vitess,pivanof/vitess,HubSpot/vitess,aaijazi/vitess,dumbunny/vitess,dcadevil/vitess,applift/vitess,AndyDiamondstein/vitess,vitessio/vitess,dumbunny/vitess,AndyDiamondstein/vitess,vitessio/vitess,pivanof/vitess,sougou/vitess,aaijazi/vitess,dumbunny/vitess,sougou/vitess,davygeek/vitess,rnavarro/vitess,sougou/vitess,aaijazi/vitess,davygeek/vitess,mattharden/vitess,rnavarro/vitess,mapbased/vitess,tinyspeck/vitess,vitessio/vitess,dumbunny/vitess,davygeek/vitess,enisoc/vitess,mapbased/vitess,rnavarro/vitess,mahak/vitess,mattharden/vitess,enisoc/vitess,dumbunny/vitess,rnavarro/vitess,applift/vitess,pivanof/vitess,davygeek/vitess,rnavarro/vitess,vitessio/vitess,HubSpot/vitess,alainjobart/vitess,dcadevil/vitess,rnavarro/vitess,pivanof/vitess,enisoc/vitess,dumbunny/vitess,tirsen/vitess,HubSpot/vitess,dumbunny/vitess