remove python3 xrootd bindings

xcache.singularity.def

@@ -36,7 +36,7 @@ Purpose Xcache-for-RUCIO
   curl -s -o /etc/yum.repos.d/wlcg-centos7.repo http://linuxsoft.cern.ch/wlcg/wlcg-centos7.repo
 
   yum install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
-  yum install -y xrootd-server-${XRD_VERSION} xrootd-client-${XRD_VERSION} xrootd-${XRD_VERSION} python2-xrootd-${XRD_VERSION} python3-xrootd-${XRD_VERSION}
+  yum install -y xrootd-server-${XRD_VERSION} xrootd-client-${XRD_VERSION} xrootd-${XRD_VERSION} python2-xrootd-${XRD_VERSION}
   yum install -y xrootd-rucioN2N-for-Xcache
   yum install -y vomsxrd
   yum install -y gdb