fix code coverage shell error in travis ci yml.

Author: ShannonDing

.travis.yml

@@ -32,4 +32,4 @@ script:
   - go test ./... -coverprofile=coverage.txt -covermode=atomic
 
 after_success:
-  - bash < (curl -s https://codecov.io/bash) || echo 'Codecov failed to upload'
+  - bash <(curl -s https://codecov.io/bash) || echo 'Codecov failed to upload'