Use npm for e2e tests

Summary:
Force npm for e2e tests.
Bonus: tracked down and removed a non-standard `.done()` call that was breaking e2e tests.

Reviewed By: bestander

Differential Revision: D4153514

fbshipit-source-id: 079939874ea75c7ea6e3e5376d37873c95fc74c1

local-cli/server/util/attachHMRServer.js

@@ -319,7 +319,9 @@ function attachHMRServer({httpServer, path, packagerServer}) {
 
         client.ws.on('close', () => disconnect());
       })
-    .done();
+    .catch(err => {
+      throw err;
+    });
   });
 }
 

scripts/run-ci-e2e-tests.js

@@ -76,7 +76,7 @@ try {
   if (tryExecNTimes(
     () => {
       exec('sleep 10s');
-      return exec(`react-native init EndToEndTest --version ${PACKAGE}`).code;
+      return exec(`react-native init EndToEndTest --version ${PACKAGE} --npm`).code;
     },
     numberOfRetries,
     () => rm('-rf', 'EndToEndTest'))) {