[trac981] Fix problem when running server_common tests

Explicitly link in liblog.

src/lib/server_common/tests/Makefile.am

@@ -40,6 +40,7 @@ run_unittests_LDADD += $(top_builddir)/src/lib/asiodns/libasiodns.la
 run_unittests_LDADD += $(top_builddir)/src/lib/cc/libcc.la
 run_unittests_LDADD += $(top_builddir)/src/lib/acl/libacl.la
 run_unittests_LDADD += $(top_builddir)/src/lib/util/libutil.la
+run_unittests_LDADD += $(top_builddir)/src/lib/log/liblog.la
 run_unittests_LDADD += $(top_builddir)/src/lib/dns/libdns++.la
 run_unittests_LDADD += $(top_builddir)/src/lib/util/unittests/libutil_unittests.la
 run_unittests_LDADD += $(top_builddir)/src/lib/exceptions/libexceptions.la