flume-ng script issue with sourcing flume-env.sh

In the bin/flume-ng script, I see:

1. allow users to override the default env vars via conf/flume-env.sh
   if [ -z "$opt_conf" ]; then
   warn "No configuration directory set! Use --conf <dir> to override."
   elif [ -f "$opt_conf/flume-env.sh" ]; then
   info "Sourcing environment configuration script $opt_conf/flume-env.sh"
   source "$opt_conf/flume-env.sh"
   fi

...but if the $opt_conf has zero length, then that means the elif would try looking for flume-env.sh at the root dir, "/flume-env.sh". I don't think that is the intent. In a previous version of this script, there was a FLUME_CONF_DIR variable that was used for this kind of case. I'm not sure what happened to it, it seems to have been removed. Previously, the user was able to set a FLUME_CONF_DIR environment var to point to wherever the conf dir was (which might not necessarily be under FLUME_HOME... for example, user could choose to move the conf dir to /etc/flume-ng/conf).