CI: add missing python package. (#10307)

.travis.yml

@@ -36,16 +36,14 @@ addons:
       - ccache
   ssh_known_hosts: 13.229.163.131
 before_install:
+  - sudo pip install -r $TRAVIS_BUILD_DIR/python/requirements.txt
+  - sudo pip install wheel sphinx==1.5.6 recommonmark sphinx-rtd-theme==0.1.9 virtualenv pre-commit
   - |
     function timeout() { perl -e 'alarm shift; exec @ARGV' "$@"; }
 script:
   - |
     # 43min timeout
-    if [[ "$JOB" != "doc" ]]; then
-      timeout 2580 paddle/scripts/paddle_docker_build.sh ${JOB}
-    else
-      timeout 2580 paddle/scritps/paddle_build.sh doc 
-    fi
+    if [[ "$JOB" != "doc" ]]; then timeout 2580 paddle/scripts/paddle_docker_build.sh ${JOB}; else timeout 2580 paddle/scritps/paddle_build.sh ${JOB}; fi; 
     if [ $? -eq 0 ] || [ $? -eq 142 ]; then true; else exit 1; fi;
   - |
     if [[ "$JOB" != "doc" ]]; then exit 0; fi;