* Some 400 Sudanese and Eritreans in "open" detention centre
* Israel sees African migrants as illegal job-seekers
* Seeking asylum, they can be held indefinitely under law
By Allyn Fisher-Ilan
HOLOT, Israel, Feb 14 (Reuters) - A compound of one-storey buildings deep in the southern Israeli desert is now home to some 400 African migrants who face the prospect of being held in custody ...