switch to rc5 since rucioN2N plugin doesn't like release 5

xcache.singularity.def

@@ -27,11 +27,11 @@ Purpose Xcache-for-RUCIO
 
 %post
 
-  XRD_VERSION="5.0.0-1.el7.x86_64"
+  XRD_VERSION="5.0.0-0.rc5.el7.x86_64"
 
   yum install -y curl gperftools hostname
 
-  curl -s -L -o /etc/yum.repos.d/xrootd-stable-slc7.repo http://www.xrootd.org/binaries/xrootd-stable-slc7.repo
+  curl -s -L -o /etc/yum.repos.d/xrootd-testing-slc7.repo http://www.xrootd.org/binaries/xrootd-testing-slc7.repo
   curl -s -o /etc/pki/rpm-gpg/RPM-GPG-KEY-wlcg http://linuxsoft.cern.ch/wlcg/RPM-GPG-KEY-wlcg
   curl -s -o /etc/yum.repos.d/wlcg-centos7.repo http://linuxsoft.cern.ch/wlcg/wlcg-centos7.repo