virt-aa-helper: Remove duplicate linking with src/datatypes.o

virt-aa-helper: Remove duplicate linking with src/datatypes.o

"virt-aa-helper" links, amongst others, against "datatypes.o" and
"libvirt.so". The latter links against "libvirt_driver.a" which in turn
also links against "datatypes.o", leading to a One-Definition-Rule
violoation for "virConnectClass" et al. in "datatypes.c".

Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>