Memory returned by get_relocated_path must be freed with
free or g_free depending on the path that the function
took; Coverity takes exception to this practice. The
fix lets caller use g_free as is standard in QEMU.
While at it, mention the requirements on the caller in
the doc comment.
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>