disabled travis linux job

.travis.yml

@@ -39,7 +39,7 @@ jobs:
 
     - stage: 'Docs'
       os: linux
-      if: branch = master
+      if: branch = xxx
       script:
         - set -e
         - openssl aes-256-cbc -K $encrypted_4e2fb4889ef8_key -iv $encrypted_4e2fb4889ef8_iv -in .travis.ssh.key.enc -out .travis.ssh.key -d