nmap: bump to version 7.70

Drop libssh2 configure test fix; the issue is fixed upstream.

Add license file hash.

Cc: Carlos Santos <casantos@datacom.ind.br>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>