build: fix link error with appArmor

Commit bb705e25 missed that the appArmor helper file also needs to
resolve the new symbols dragged in by domain_conf.c.

* src/Makefile.am (SECURITY_DRIVER_APPARMOR_HELPER_SOURCES): Pull
in datatypes.c.

src/Makefile.am

@@ -405,6 +405,7 @@ LXC_CONTROLLER_SOURCES =					\
 		lxc/lxc_controller.c
 
 SECURITY_DRIVER_APPARMOR_HELPER_SOURCES =			\
+		$(DATATYPES_SOURCES)				\
 		security/virt-aa-helper.c
 
 PHYP_DRIVER_SOURCES =						\