upgrade to elasticsearch 6.2.4

Dockerfile

@@ -1,14 +1,6 @@
-FROM elasticsearch:2.1
-MAINTAINER Bachue Zhou "bachue.shu@gmail.com"
+FROM docker.elastic.co/elasticsearch/elasticsearch:6.2.4
+MAINTAINER Rong Zhou "zhourong@qiniu.com"
 
-RUN echo 'deb http://mirrors.aliyun.com/debian/ jessie main non-free contrib' > /etc/apt/sources.list && \
-    apt-get update && \
-    apt-get install -y --no-install-recommends --force-yes maven openjdk-8-jdk && \
-    rm -rf /var/lib/apt/lists/*
-ADD https://github.com/medcl/elasticsearch-analysis-ik/archive/v1.7.0.tar.gz /tmp/elasticsearch-analysis-ik.tar.gz
-RUN tar -xvf /tmp/elasticsearch-analysis-ik.tar.gz -C /tmp && \
-    cd /tmp/elasticsearch-analysis-ik-1.7.0 && \
-    mvn package && \
-    unzip target/releases/elasticsearch-analysis-ik-1.7.0.zip -d /usr/share/elasticsearch/plugins/ik && \
-    cd / && \
-    rm -rf /tmp/elasticsearch-analysis-ik*
+RUN wget -c --tries=0 -O /tmp/elasticsearch-analysis-ik.zip https://github.com/medcl/elasticsearch-analysis-ik/releases/download/v6.2.4/elasticsearch-analysis-ik-6.2.4.zip && \
+    unzip /tmp/elasticsearch-analysis-ik.zip -d /usr/share/elasticsearch/plugins && \
+    rm -rf /tmp/elasticsearch-analysis-ik.zip