The 'kdgb' is allocating memory in get_kdbg(), but it is not freed
in both fill_header() and fill_context() failed branches, fix it.

Signed-off-by: AlexChen <alex.chen@huawei.com>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Reviewed-by: Viktor Prutyanov <viktor.prutyanov@phystech.edu>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <5F463659.8080101@huawei.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>