Prevent default TravisCI install action

.travis.yml

@@ -25,5 +25,10 @@ go:
     - tip
     - 1.12.x
 
+install:
+    - # Do nothing. This is needed to prevent the default install action
+      # "go get -t -v ./..." from happening here because we want it to happen
+      # inside script step.
+
 script:
     - go test -v -race -mod=readonly ./...