cmd/go: do not ignore DepsErrors in 'go run'
cmd/go: do not ignore DepsErrors in 'go run'

Fixes issue 3490.

R=golang-dev, dave, rsc
CC=golang-dev
http://codereview.appspot.com/6040046

Committer: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang