remove travis config (#6199)

.travis.yml

@@ -1,23 +0,0 @@
-language: go
-
-go:
-  # Please keep this in-sync with the go version we build against in
-  # build-support/docker/Build-Go.dockerfile.
-  - "1.12.1"
-
-branches:
-  only:
-    - master
-    - release/1-6
-
-matrix:
-  include:
-    - env: GOTEST_PKGS="./api"
-    - env: GOTEST_PKGS="./agent"
-    - env: GOTEST_PKGS="./agent/consul"
-    - env: GOTEST_PKGS_EXCLUDE="./api|./agent|./agent/consul"
-
-script:
-  - make test-ci
-
-sudo: false