move no fallback env var to npm test script

.travis.yml

@@ -3,8 +3,6 @@ node_js:
   - "0.10"
 addons:
   firefox: "34.0"
-env:
-  - ECCRYPTO_NO_FALLBACK=1
 notifications:
   email:
     on_success: never

package.json

@@ -6,7 +6,7 @@
   "browser": "browser.js",
   "scripts": {
     "install": "node-gyp rebuild || exit 0",
-    "test": "mocha && xvfb-run -a karma start && jshint .",
+    "test": "ECCRYPTO_NO_FALLBACK=1 mocha && xvfb-run -a karma start && jshint .",
     "m": "mocha",
     "k": "xvfb-run -a karma start",
     "kc": "xvfb-run -a karma start --browsers Chromium",