Exemption mkldnn (#1155)

* Exemption mkldnn

* update

* test=develop

scripts/checkapproval.sh

@@ -2,7 +2,7 @@
 
 API_FILES=("doc/fluid")
 for API_FILE in ${API_FILES[*]}; do
-  API_CHANGE=`git diff --name-only upstream/$BRANCH | grep "${API_FILE}" || true`
+  API_CHANGE=`git diff --name-only upstream/$BRANCH | grep "${API_FILE}" | grep -v "doc/fluid/design/mkldnn" || true`
   if [ "${API_CHANGE}" ];then
     approval_line=`curl -H "Authorization: token ${GITHUB_API_TOKEN}" https://api.github.com/repos/PaddlePaddle/FluidDoc/pulls/${GIT_PR_ID}/reviews?per_page=10000`
     if [ "${API_FILE}" == "doc/fluid" ];then