tests/build-test-snapd-snap: snapcraft pack (#17847)

Snapcraft keeps complaining about missing 'pack' argument.

Signed-off-by: Maciej Borzecki <maciej.borzecki@canonical.com>

Author: bboozzoo

tests/build-test-snapd-snap

@@ -65,7 +65,7 @@ if [ -z "$SNAPCRAFT_NO_CLEAN" ] && [ "$no_clean" != "1" ]; then
     snapcraft --verbose clean $snapd_clean_arg
 fi
 
-snapcraft --verbose
+snapcraft --verbose pack
 
 for snap_file in snapd_1337.*.snap; do
     mv "${snap_file}" built-snap/"${snap_file}.keep"