Travis CI Linux VM axel downloads error

[wangkuiyi]

We need to install it, otherwise the following script errors

sqlflow/scripts/travis/deploy_client.sh

Line 64 in 185be33

sudo unzip -qq p.zip -d /usr/local

[wangkuiyi]

set -x to debug deploy_client.sh

[wangkuiyi]

It is not because Travis CI Linux build doesn't have unzip.

The reason is that axel complains about "too many redirects" (log)

Install protoc ...
+PROTOC_SITE=https://github.com/protocolbuffers/protobuf/releases
+axel https://github.com/protocolbuffers/protobuf/releases/download/v3.7.1/protoc-3.7.1-linux-x86_64.zip
Initializing download: https://github.com/protocolbuffers/protobuf/releases/download/v3.7.1/protoc-3.7.1-linux-x86_64.zip
Too many redirects.

[wangkuiyi]

According to the log

axel --version
Axel version 2.5 (Linux)
Copyright 2001-2007 Wilmer van der Gaast,
          2015      Joao Eriberto Mota Filho,
                    and others.

I am using Ubuntu Xenial (16.04) in the VM.

[wangkuiyi]

After chooing Ubuntu Bionic in .travis.yml, apt-get install axel gave me version 2.16.1, which doesn't complain "too many redirects". FYI @lhw362950217

dist: bionic