Change: Reduce RHEL image size by calling "yum clean all" after insta…

…lling packages. (#67)

operating_systems/rhel/Dockerfile

@@ -9,10 +9,9 @@ RUN if [ "$UPDATED" = true ]; then \
     # Pinning minor version is impossible because of missing separate repository.
     # Workaround: Exclude release files (e.g. /etc/os-release)
     # for RHEL 7 and RHEL 8 or higher, respectively
-    yum upgrade -y --exclude redhat-release-server --exclude redhat-release \
-    && yum clean all; \
-    fi \
+    yum upgrade -y --exclude redhat-release-server --exclude redhat-release; fi \
     && yum install -y openssh-server \
+    && yum clean all \
     && useradd demo \
     && echo "demo" | passwd --stdin demo \
     && ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key -N "" \