fix rpms

Signed-off-by: Jessica Frazelle <princess@docker.com>

contrib/builder/rpm/centos-7/Dockerfile

@@ -5,6 +5,7 @@
 FROM centos:7
 
 RUN yum groupinstall -y "Development Tools"
+RUN yum -y swap -- remove systemd-container systemd-container-libs -- install systemd systemd-libs
 RUN yum install -y btrfs-progs-devel device-mapper-devel glibc-static libselinux-devel sqlite-devel tar
 
 ENV GO_VERSION 1.4.2

contrib/builder/rpm/generate.sh

@@ -38,6 +38,10 @@ for version in "${versions[@]}"; do
 		centos:*)
 			# get "Development Tools" packages dependencies
 			echo 'RUN yum groupinstall -y "Development Tools"' >> "$version/Dockerfile"
+
+			if [[ "$version" == "centos-7" ]]; then
+				echo 'RUN yum -y swap -- remove systemd-container systemd-container-libs -- install systemd systemd-libs' >> "$version/Dockerfile"
+			fi
 			;;
 		*)
 			echo 'RUN yum install -y @development-tools fedora-packager' >> "$version/Dockerfile"