Enable shell tests

We need to use sudo: required, and dist: trusty to avoid old versions of
bash in travis which don't support the -n argument to the `wait` shell
built-in.

We had to disable the -e checks in etcd.sh since the killall || killall
parts were causing those to trigger in travis.

test.sh

@@ -19,5 +19,5 @@ go vet && echo PASS
 # do these longer tests only when running on ci
 if env | grep -q -e '^TRAVIS=true$' -e '^JENKINS_URL='; then
 	go test -race
-	#./test/test-shell.sh
+	./test/test-shell.sh
 fi