HADOOP-14474. Use OpenJDK 7 instead of Oracle JDK 7 to avoid oracle-java7-installer failures. Contributed by Akira Ajisaka.

dev-support/docker/Dockerfile

@@ -80,10 +80,6 @@ RUN apt-get -q install --no-install-recommends -y software-properties-common
 RUN add-apt-repository -y ppa:webupd8team/java
 RUN apt-get -q update
 
-# Auto-accept the Oracle JDK license
-RUN echo oracle-java7-installer shared/accepted-oracle-license-v1-1 select true | sudo /usr/bin/debconf-set-selections
-RUN apt-get -q install --no-install-recommends -y oracle-java7-installer
-
 # Auto-accept the Oracle JDK license
 RUN echo oracle-java8-installer shared/accepted-oracle-license-v1-1 select true | sudo /usr/bin/debconf-set-selections
 RUN apt-get -q install --no-install-recommends -y oracle-java8-installer