tests: fixed test failures caused by using non-perlbrew cpanm in travis.

Author: xiaocang

.travis.yml

@@ -33,8 +33,8 @@ env:
 install:
   - if [ ! -d download-cache ]; then mkdir download-cache; fi
   - if [ ! -f download-cache/openssl-$OPENSSL_VER.tar.gz ]; then wget -O download-cache/openssl-$OPENSSL_VER.tar.gz https://www.openssl.org/source/openssl-$OPENSSL_VER.tar.gz; fi
-  - sudo apt-get install -qq -y cpanminus axel
-  - sudo cpanm --notest Test::Nginx > build.log 2>&1 || (cat build.log && exit 1)
+  - sudo apt-get install -qq -y axel
+  - cpanm --sudo --notest Test::Nginx > build.log 2>&1 || (cat build.log && exit 1)
   - wget http://nginx.org/download/nginx-${NGINX_VERSION}.tar.gz
   - git clone https://github.com/openresty/openresty.git ../openresty
   - git clone https://github.com/openresty/nginx-devel-utils.git