1.1.1: Dockerfile intermediate container (#189)

* Create intermediate container for OS deps to speed up download/build

Dockerfile

@@ -2,8 +2,8 @@ FROM centos:centos7
 ARG RELEASE
 MAINTAINER Tim Vaillancourt <tim.vaillancourt@percona.com>
 RUN yum install -y https://www.percona.com/redir/downloads/percona-release/redhat/latest/percona-release-0.1-4.noarch.rpm epel-release && \
-	yum install -y Percona-Server-MongoDB-34-tools zbackup && yum clean all && \
-	curl -Lo /usr/bin/mongodb-consistent-backup https://github.com/Percona-Lab/mongodb_consistent_backup/releases/download/$RELEASE/mongodb-consistent-backup.el7.centos.x86_64 && \
+	yum install -y Percona-Server-MongoDB-34-tools zbackup && yum clean all
+RUN curl -Lo /usr/bin/mongodb-consistent-backup https://github.com/Percona-Lab/mongodb_consistent_backup/releases/download/$RELEASE/mongodb-consistent-backup.el7.centos.x86_64 && \
 	chmod +x /usr/bin/mongodb-consistent-backup
 ENTRYPOINT ["mongodb-consistent-backup"]
 CMD ["--help"]