rmv go master

.travis.yml

@@ -9,9 +9,7 @@ jobs:
   include:
     - stage: check_fmt
       sudo: require
-      go:
-        - "1.9"
-        - master
+      go: "1.9.x"
       install:
         - go get -u golang.org/x/tools/cmd/goimports
         - go get -u gopkg.in/alecthomas/gometalinter.v2
@@ -23,6 +21,7 @@ jobs:
         - make linter
 
     - stage: test
+      go: "1.9.x"
       before_install:
         - go get -t -v ./...
       install: skip