add check need build paddle

ci_scripts/check_api_cn.sh

 #!/bin/bash
+set -ex
 
-git_files=`git diff --numstat upstream/$BRANCH | awk '{print $NF}'`
+function build_paddle() {
+    git clone https://github.com/PaddlePaddle/Paddle.git
+    mkdir Paddle/build
+    cd Paddle/build
 
-for file in `echo $git_files`;do
-  grep "code-block" ../$file
-  if [ $? -eq 0 ] ;then 
-    echo $file | grep "doc/paddle/api/paddle/.*_cn.rst"
-    if [ $? -eq 0 ];then
-        api_file=`echo $file | sed 's#doc/paddle/api/##g'`
-        grep -w "${api_file}" ${DIR_PATH}/api_white_list.txt
-        if [ $? -ne 0 ];then
-            python chinese_samplecode_processor.py ../$file
-            if [ $? -ne 0 ];then
-                echo "chinese sample code failed"
-                exit 5
+    cmake .. -DWITH_GPU=ON  -DWITH_COVERAGE=OFF -DWITH_TESTING=OFF -DCMAKE_BUILD_TYPE=Release
+    make -j`nproc`
+    pip install -U python/dist/paddlepaddle_gpu-0.0.0-cp27-cp27mu-linux_x86_64.whl
+}
+
+need_check_files=""
+function find_need_check_files() {
+    git_files=`git diff --numstat upstream/$BRANCH | awk '{print $NF}'`
+
+    for file in `echo $git_files`;do
+        grep "code-block" ../$file
+        if [ $? -eq 0 ] ;then 
+            echo $file | grep "doc/paddle/api/paddle/.*_cn.rst"
+            if [ $? -eq 0 ];then
+                api_file=`echo $file | sed 's#doc/paddle/api/##g'`
+                grep -w "${api_file}" ${DIR_PATH}/api_white_list.txt
+                if [ $? -ne 0 ];then
+                    need_check_files="${need_check_files} $file"
+                fi 
             fi
-        fi 
+        fi
+    done
+}
+
+find_need_check_files
+if [ -z "$need_check_files" ]
+then
+    echo "need check files is empty, skip chinese api check"
+else
+    echo "need check files is not empty, begin to build and install paddle"
+    build_paddle
+    if [ $? -ne 0 ];then
+      echo "paddle build error"
+      exit 5
     fi
-  fi
-done
 
+    for file in $need_check_files;do
+        python chinese_samplecode_processor.py ../$file
+        if [ $? -ne 0 ];then
+            echo "chinese sample code failed"
+            exit 5
+        fi
+    done
+fi