go/printer: fix sync bug - avoid sending on errors twice - 	and report node type in error
go/printer: fix sync bug - avoid sending on errors twice -
	and report node type in error

R=gri
DELTA=4  (3 added, 0 deleted, 1 changed)
OCL=34949
CL=34955

tav/go,tav/go,tav/go,tav/go,tav/go,tav/go,tav/go