Enable OpenVZ on Linux only

Closes: #630099

debian/rules

@@ -21,6 +21,7 @@ ifneq (,$(findstring $(DEB_HOST_ARCH_OS), linux))
   WITH_MACVTAP        = --with-macvtap
   WITH_NETWORK        = --with-network
   WITH_QEMU           = --with-qemu
+  WITH_OPENVZ         = --with-openvz
   ifneq (,$(findstring $(DEB_HOST_ARCH), ia64))
       WITH_LXC        = --without-lxc
   else
@@ -48,7 +49,7 @@ DEB_CONFIGURE_EXTRA_FLAGS :=     \
 	$(WITH_QEMU)		 \
 	--with-qemu-user=libvirt-qemu  \
 	--with-qemu-group=kvm    \
-	--with-openvz            \
+        $(WITH_OPENVZ)		 \
 	--with-avahi             \
 	--with-sasl              \
 	$(WITH_POLKIT)		 \