virSecretLoadAllConfigs: Use g_autofree for @path

virSecretLoadAllConfigs: Use g_autofree for @path

When loading virSecret configs, the @path variable holds path to
individual config files. In each iteration it is freed explicitly
using VIR_FREE(). Switch it to g_autofree and remove those
explicit calls.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>