dup: fixed bandwidth vs desturl testing

handlers/dup.in

@@ -107,7 +107,7 @@ duplicity_sub="`echo $duplicity_version | @AWK@ -F '.' '{print $3}'`"
 
 scpoptions="$sshoptions"
 if [ "$bandwidthlimit" != 0 ]; then
-   [ -z "$testurl" ] || warning 'The bandwidthlimit option is not used when desturl is set.'
+   [ -z "$desturl" ] || warning 'The bandwidthlimit option is not used when desturl is set.'
    scpoptions="$scpoptions -l $bandwidthlimit"
 fi