build: update travis with zmq

.travis.yml

@@ -1,7 +1,7 @@
 sudo: false
 language: node_js
 env:
-  - BITCORENODE_ENV=test BITCORENODE_ASSUME_YES=true CXX=g++-4.8 CC=gcc-4.8
+  - CXX=g++-4.8 CC=gcc-4.8
 addons:
   apt:
     sources:
@@ -9,14 +9,13 @@ addons:
     packages:
       - g++-4.8
       - gcc-4.8
+      - libzmq3-dev
 node_js:
   - "v0.12.7"
   - "v4"
 script:
+  - _mocha -R spec integration/p2p.js
   - _mocha -R spec integration/regtest.js
   - _mocha -R spec integration/regtest-node.js
-  - _mocha -R spec integration/p2p.js
   - _mocha -R spec --recursive
-cache:
-  directories:
-    - cache
+