glib-2.0: Wrap TimeZone.identifier() constuctor for proper error support
glib-2.0: Wrap TimeZone.identifier() constuctor for proper error support

This allows to handle possible null returned by this constructor.

GNOME/vala,GNOME/vala,frida/vala,frida/vala,frida/vala,frida/vala,GNOME/vala,frida/vala,GNOME/vala