Fix: param-validation: remove memory leaks

Fix: param-validation: remove memory leaks

The GArray allocated in bt_param_validation_validate is never freed, fix
that.  Furthermore, there's a spurious call to
g_ptr_array_new_with_free_func that shouldn't be there, probably the
result of a bad merge or bad edit, causing another leak.  Remove that
one.

Change-Id: I89afeaa7e6ee67b6536daa42dc2c6d74ec79ae0c
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/2233
Tested-by: jenkins <jenkins@lttng.org>
Reviewed-by: Francis Deslauriers <francis.deslauriers@efficios.com>