build: Add lxc testcase to dist list

Introduced by commit 3f029fb5 the RPM build
was broken due to a missing LXC textcase.
Signed-off-by: NDaniel Hansel <daniel.hansel@linux.vnet.ibm.com>
(cherry picked from commit 6285c17f)

tests/Makefile.am

@@ -54,6 +54,7 @@ EXTRA_DIST =		\
 	domainsnapshotxml2xmlout \
 	interfaceschemadata \
 	lxcxml2xmldata \
+	lxcxml2xmloutdata \
 	networkschematest \
 	networkxml2xmlin \
 	networkxml2xmlout \