minor update to fix dockerfile error

Author: glw

Dockerfile

@@ -44,7 +44,7 @@ RUN tar -xf gdal-${GDAL_VERSION}.tar.xz \
            && ./configure --with-python --with-geos --with-geotiff --with-jpeg \
            && make && make install && ldconfig \
            && apt-get update -y \
-           && apt-get remove -y --purge build-essential
+           && apt-get remove -y --purge build-essential \
            #&& cd $ROOTDIR && cd src/gdal-${GDAL_VERSION}/swig/python \
            #&& python3 setup.py build \
            #&& python3 setup.py install \
@@ -106,4 +106,4 @@ ADD https://raw.githubusercontent.com/glw/docker_python3_opencv_exiv2/master/NDV
 ADD https://raw.githubusercontent.com/glw/docker_python3_opencv_exiv2/master/tiff_2_jpg_convert.py /data
 ADD https://raw.githubusercontent.com/glw/docker_python3_opencv_exiv2/master/write_colormap_file.py /data
 
-CMD ["/bin/bash"]
+CMD ["/bin/bash"]