virusbmock: Link with libvirt_utils

We are using couple of functions from there (e.g. virStrdup) and
rely that the binary linking us has the libvirt_utils linked
already. Well, this makes valgrind sad.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

tests/Makefile.am

@@ -1203,7 +1203,8 @@ virnetdevbandwidthtest_LDADD = $(LDADDS) $(LIBXML_LIBS)
 virusbmock_la_SOURCES = virusbmock.c
 virusbmock_la_CFLAGS = $(AM_CFLAGS)
 virusbmock_la_LDFLAGS = $(MOCKLIBS_LDFLAGS)
-virusbmock_la_LIBADD = $(MOCKLIBS_LIBS)
+virusbmock_la_LIBADD = $(MOCKLIBS_LIBS) \
+	../src/libvirt_util.la
 
 virnetdevbandwidthmock_la_SOURCES = \
 	virnetdevbandwidthmock.c