fix: [rsync-backup-target] ensure that non data output of ``compose-add-rsync-key`` is cast on stderr

Signed-off-by: Valentin Lab <valentin.lab@kalysto.org>

rsync-backup-target/resources/bin/compose-add-rsync-key

@@ -77,7 +77,7 @@ cmdline.spec::cmd:__main__:run() {
         fi
 
         if [ "${prev_key}" == "$SSH_PUBLIC_KEY" ]; then
-            echo "Key was already setup."
+            info "Key is already setup correctly."
             exit 0
         fi
 
@@ -137,13 +137,13 @@ EOF
         ## reloading (could be much faster)
         compose --debug down && compose --debug up
         if [ "$?" == 0 ]; then
-            echo "Added key, and restarted service ${DARKYELLOW}$service_name${NORMAL}."
+            info "Added key, and restarted service ${DARKYELLOW}$service_name${NORMAL}."
         else
-            echo "something went wrong ! Should check the state of '$DOMAIN' !!"
+            err "something went wrong ! Should check the state of '$DOMAIN' !!"
             exit 1
         fi
     else
-        echo "Added key, you'll need to restart service ${DARKYELLOW}$service_name${NORMAL}."
+        info "Added key, you'll need to restart service ${DARKYELLOW}$service_name${NORMAL}."
     fi
 }