Used fixed versions for some packages

package.json

@@ -10,7 +10,7 @@
         "url": "http://github.com/c9/core.git"
     },
     "dependencies": {
-        "acorn": ">=0.11.0",
+        "acorn": "2.5.2",
         "async": "^0.9.0",
         "base64id": "~0.1.0",
         "connect": "~2.12.0",
@@ -42,7 +42,7 @@
         "read": "~1.0.5",
         "form-data": "~0.2.0",
         "chai": "~1.5.0",
-        "mocha": "~2.3.3"
+        "mocha": "1.8.2"
     },
     "devDependencies": {},
     "licenses": [],