Dockerfile 优化 (#453)

Dockerfile-py3

@@ -3,14 +3,14 @@ LABEL MAINTAINER Jumpserver Team <ibuler@qq.com>
 
 WORKDIR /tmp
 
-RUN yum -y install wget sqlite-devel xz gcc automake zlib-devel openssl-devel
+RUN yum -y install wget sqlite-devel xz gcc automake zlib-devel openssl-devel; yum clean all
 
 # Install Python
 RUN wget https://www.python.org/ftp/python/3.6.1/Python-3.6.1.tar.xz && \
-    tar xvf Python-3.6.1.tar.xz  && cd Python-3.6.1 && ./configure && make && make install
+    tar xvf Python-3.6.1.tar.xz  && cd Python-3.6.1 && ./configure && make && make install &&  \
+    rm -rf /tmp/{Python-3.6.1.tar.xz,Python-3.6.1}
 
 RUN mv /usr/bin/python /usr/bin/python2
 RUN ln -s /usr/local/bin/python3 /usr/bin/python && ln -s /usr/local/bin/pip3 /usr/bin/pip
 RUN sed -i 's@/usr/bin/python@/usr/bin/python2@g' /usr/bin/yum
 
-RUN rm -rf /tmp/{Python-3.6.1.tar.xz,Python-3.6.1}