fix infinite loop on windows when read() returns 0 in gg_file_hash_sha1_part
fix infinite loop on windows when read() returns 0 in gg_file_hash_sha1_part

Signed-off-by: Rafał Przemysław Malinowski <b8f60c52f3f0b57a213b606f2d63f58ef0768b73@gmail.com>

clokep/libgadu,wojtekka/libgadu,wojtekka/libgadu,wojtekka/libgadu,clokep/libgadu,clokep/libgadu