fix installing apex in gpu base image

docker/Dockerfile.ubuntu_base

@@ -186,14 +186,15 @@ RUN if [ "$USE_GPU" = "True" ] ; then \
 RUN if [ "$USE_GPU" = "True" ] ; then \
        export TORCH_CUDA_ARCH_LIST="6.0;6.1;7.0;7.5;8.0;8.9;9.0;8.6+PTX" && pip install --no-cache-dir git+https://github.com/gxd1994/Pointnet2.PyTorch.git@master#subdirectory=pointnet2; \
     else \
-     echo 'cpu unsupport Pointnet2'; \
+     echo 'CPU env does not support Pointnet2'; \
     fi
 
 # NVIDIA apex building
 RUN if [ "$USE_GPU" = "True" ] ; then \
+        pip install --no-cache-dir packaging &&\
         bash /tmp/install_apex.sh; \
     else \
-     echo 'cpu unsupport nvidia apex'; \
+     echo 'CPU env does not support NVIDIA Apex.'; \
     fi
 
 

docker/scripts/install_apex.sh

@@ -3,6 +3,5 @@ export MAX_JOBS=16 \
 && cd apex \
 && git checkout 6bd01c4b99a84648ad5e5238a959735e6936c813 \
 && TORCH_CUDA_ARCH_LIST="6.0;6.1;6.2;7.0;7.5;8.0;8.9;9.0;8.6+PTX" pip install -v --disable-pip-version-check --no-cache --global-option="--cpp_ext" --global-option="--cuda_ext" ./ \
-&& pip install packaging \
 && cd .. \
 && rm -rf apex