update-kernel: Slightly improve messaging about new flavours

UI/UX.

Signed-off-by: Vitaly Chikunov <vt@altlinux.org>

update-kernel

@@ -434,8 +434,12 @@ for try in 1 2; do
 	else
 		current_kver=$uname_r
 	fi
-	echo "Searching for a newer flavour..."
+	echo "Searching for a newer flavour (>= $current_kver)..."
 	kernel_flavour=$(next_flavours "$current_kver" | tail -1)
+	if [ -z "$kernel_flavour" ]; then
+	       echo "No newer flavours found."
+	       break
+	fi
 	echo "Upgrade to the next available flavour $kernel_flavour"
 done
 [ "$num_available_kernels" -ne 0 ] || fatal "Use -t to select another flavour."