all-qemu.bash: remove DISABLE_NET_TESTS
all-qemu.bash: remove DISABLE_NET_TESTS

It's no longer used.

R=adg
CC=golang-dev
http://codereview.appspot.com/4426061
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go