Cleanup references to Travis CI (#4208)

Broken since 4efb0b78

docs/test_cases.md

-Travis CI test matrix
-=====================
-
-GCE instances
--------------
-
-Here is the test matrix for the CI gates:
-
-|           Network plugin|                  OS type|               GCE region|             Nodes layout|
-|-------------------------|-------------------------|-------------------------|-------------------------|
-|                    canal|       debian-8-kubespray|             asia-east1-a|                 ha-scale|
-|                   calico|       debian-8-kubespray|           europe-west1-c|                  default|
-|                  flannel|                 centos-7|        asia-northeast1-c|                  default|
-|                   calico|                 centos-7|            us-central1-b|                       ha|
-|                    weave|                   rhel-7|               us-east1-c|                  default|
-|                    canal|            coreos-stable|               us-west1-b|                 ha-scale|
-|                    canal|                   rhel-7|        asia-northeast1-b|                 separate|
-|                    weave|       ubuntu-1604-xenial|           europe-west1-d|                 separate|
-|                   calico|            coreos-stable|            us-central1-f|                 separate|
-
-
 Node Layouts
 ------------
 
@@ -41,15 +20,6 @@ never actually deployed, but certificates are generated for them.
 
 Note, the canal network plugin deploys flannel as well plus calico policy controller.
 
-Hint: the command
-```
-bash scripts/gen_matrix.sh
-```
-will (hopefully) generate the CI test cases from the current ``.travis.yml``.
-
-Gitlab CI test matrix
-=====================
-
 GCE instances
 -------------
 

scripts/gen_matrix.sh

-#!/bin/sh
-# Generates MD formatted CI matrix from the .travis.yml
-a=$(perl -ne '/^\s{6}(CLOUD_IMAGE|KUBE_NETWORK_PLUGIN|CLOUD_REGION|CLUSTER_MODE)=(\S+)$/ && print "$2\n"' .travis.yml.bak)
-echo Travis-CI
-printf "|%25s|%25s|%25s|%25s|\n" "Network plugin" "OS type" "GCE region" "Nodes layout"
-echo "|-------------------------|-------------------------|-------------------------|-------------------------|"
-c=0
-for i in `echo $a`; do
-  printf "|%25s" $i
-  [ $(($c % 4)) -eq 3 ] && printf "|\n"
-  c=$(( c + 1))
-done
-
-echo
-a=$(perl -ne '/^#\sstage:\sdeploy-gce-(\S+)$/ && print "$1\n";/^\s{2}(CLOUD_IMAGE|KUBE_NETWORK_PLUGIN|CLOUD_REGION|CLUSTER_MODE):\s(\S+)$/ && print "$2\n"' .gitlab-ci.yml)
-echo Gitlab-CI
-printf "|%20s|%20s|%20s|%20s|%20s\n"  "Stage" "Network plugin" "OS type" "GCE region" "Nodes layout"
-echo "|--------------------|--------------------|--------------------|--------------------|--------------------|"
-c=0
-for i in `echo $a`; do
-  printf "|%20s" $i
-  [ $(($c % 5)) -eq 4 ] && printf "|\n"
-  c=$(( c + 1))
-done