add travis_wait to test job

in an attempt to counter the frequent "no output received" problem

.travis.yml

@@ -17,7 +17,7 @@ cache:
 
 script:
   - go build ./...
-  - go test -v -race -coverprofile=coverage.txt -covermode=atomic ./...
+  - travis_wait go test -v -race -coverprofile=coverage.txt -covermode=atomic ./...
 
 after_success:
   - bash <(curl -s https://codecov.io/bash)