sync_from_old_server.sh: get rid of unused var 'ssh_config_exists'.

sync_from_old_server.sh

@@ -285,7 +285,6 @@ if [[ -f "/root/.ssh/config" ]] ; then
    mv "/root/.ssh/config " "/root/.ssh/config.${cur_date}"  > /dev/null 2> $tmp_err_msg
    if [[ $? -eq 0 ]];then
       echo_ok
-      ssh_config_exists=true
    else
       echo_failed
       error "$(cat $tmp_err_msg)"
@@ -302,7 +301,6 @@ if [[ -f "/root/.ssh/config" ]] ; then
    fi
 else
    echo_skipped
-   ssh_config_exists=false
 fi