Update zookeeper download URL and switch to 1.3.1 for travis

.travis.yml

@@ -1,20 +1,20 @@
 language: go
 go:
-  - 1.1.2
+  - 1.3.1
   - tip
 
 branches:
   only:
     - master
 
 before_install:
-  - wget http://mirrors.sonic.net/apache/zookeeper/zookeeper-3.4.5/zookeeper-3.4.5.tar.gz
+  - wget http://apache.claz.org/zookeeper/zookeeper-3.4.6/zookeeper-3.4.6.tar.gz
   - tar -zxvf zookeeper*tar.gz
 
 script:
   - go build ./...
   - go fmt ./...
-  - (go version | grep "version go1.1") || go get code.google.com/p/go.tools/cmd/vet
+  - go get code.google.com/p/go.tools/cmd/vet
   - go vet ./...
   - go test -i -race ./...
   - go test -v -race ./...