Removed castor-rmc-server rpm from buildtree-stage1-rpms/Dockerfile because...

Removed castor-rmc-server rpm from buildtree-stage1-rpms/Dockerfile because CTA now builds /usr/bin/cta-rmcd

continuousintegration/docker/ctafrontend/cc7/buildtree-stage1-rpms/Dockerfile

@@ -81,7 +81,6 @@ RUN yum-config-manager --enable epel --setopt="epel.priority=4" \
       mtx \
       lsscsi \
       sg3_utils \
-      castor-rmc-server \
       protobuf3 \
       cryptopp \
       json-c \