Added comments in the xroot configuration file

xroot_plugins/xrd.cf.fst

+# Load the plugin XrdProFst
 xrootd.fslib /home/dkruse/CTA/build/xroot_plugins/libXrdProFst.so
+
+# Use the Kerberos 5 security module
 xrootd.seclib libXrdSec.so
+
+# Using my own hardcoded keytab for the moment
 sec.protocol krb5 /etc/krb5.keytab.dkruse host/<host>@CERN.CH
+
+# Only Kerberos 5 is allowed
 sec.protbind * only krb5
+
+# Allow copying from absolute paths
 all.export /
+
+# Turn off asynchronous i/o
 xrootd.async off