add WITH_DOC for print_operators_doc in docker/build.sh

paddle/scripts/docker/build.sh

@@ -185,7 +185,14 @@ EOF
     ${DOCKERFILE_GPU_ENV}
     ADD go/cmd/pserver/pserver /usr/bin/
     ADD go/cmd/master/master /usr/bin/
+EOF
+
+    if [[ ${WITH_DOC:-OFF} == 'ON' ]]; then
+        cat >> /paddle/build/Dockerfile <<EOF
         ADD paddle/pybind/print_operators_doc /usr/bin/
+EOF
+    fi
+    cat >> /paddle/build/Dockerfile <<EOF
     # default command shows the paddle version and exit
     CMD ["paddle", "version"]
 EOF