fix: use correct function to print 'enum bt_ctf_scope'

fix: use correct function to print 'enum bt_ctf_scope'

Building with GCC10 results in the following error:

implicit conversion from 'enum bt_ctf_scope' to 'enum bt_field_path_scope' [-Werror=enum-conversion]

Change-Id: Id1144231f8439444696e4683dff2b0abf0d26d60
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/2851
Reviewed-by: Simon Marchi <simon.marchi@efficios.com>
Tested-by: jenkins <jenkins@lttng.org>