x86/parasite-head: add 32-bit parasite entry

To drop the second parasite blob, create another entry in 64-bit
parasite.
Didn't remove parasite-head-compat.S - it we gonna support native 32-bit
buids, we gonna need it.

travis-ci: success for Rectify 32-bit compatible C/R on x86
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>