core: fix leak

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
update NEWS

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>

Conflicts:
	NEWS
Release GPaste 3.3

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>

Conflicts:
	NEWS
	README.md