ci: discard invalid jar signatures; see https://issues.apache.org/jira/browse/ZOOKEEPER-2854

Author: James DeFelice

.travis.yml

@@ -5,15 +5,18 @@ go:
 jdk:
   - oraclejdk9
 
+env:
+  - zk_version=3.4.10
+
 sudo: false
 
 branches:
   only:
     - master
 
 before_install:
-  - wget http://apache.cs.utah.edu/zookeeper/zookeeper-3.4.10/zookeeper-3.4.10.tar.gz
-  - tar -zxvf zookeeper*tar.gz
+  - wget http://apache.cs.utah.edu/zookeeper/zookeeper-${zk_version}/zookeeper-${zk_version}.tar.gz
+  - tar -zxvf zookeeper*tar.gz && zip -d zookeeper-${zk_version}/contrib/fatjar/zookeeper-${zk_version}-fatjar.jar 'META-INF/.SF' 'META-INF/*.DSA'
   - go get github.com/mattn/goveralls
   - go get golang.org/x/tools/cmd/cover