ncftp: bump version

Due to recent 3.2.4 release, 3.2.2 download address has changed, so
I prefered bump version to 3.2.4 rather than changing NCFTP_SITE.

Signed-off-by: Julien Boibessot <julien.boibessot@armadeus.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>