change factory girl to randomise value for requested_orphan_count

OSRA-83 OSRA-84 OSRA-85 OSRA-86 #code-review
OSRA-83 #comment sponsor factory requested_orphan_count randomised
fixed incorrect generation of random data for sponsor factory

OSRA-83 OSRA-84 OSRA-85 OSRA-86 #code-review
OSRA-83 #comment sponsor factory requested_orphan_count randomised