[2198] Remove dependency on libb10-util in src/lib/util/unittests/

src/lib/util/Makefile.am

 # InterprocessSyncFile has a dependency on isc::util::thread::Mutex
-SUBDIRS = threads . io unittests tests pyunittests python
+SUBDIRS = io unittests threads . tests pyunittests python
 
 AM_CPPFLAGS = -I$(top_srcdir)/src/lib -I$(top_builddir)/src/lib
 AM_CPPFLAGS += -I$(top_srcdir)/src/lib/util -I$(top_builddir)/src/lib/util

src/lib/util/unittests/Makefile.am

@@ -21,8 +21,7 @@ if HAVE_GTEST
 libutil_unittests_la_CPPFLAGS += $(GTEST_INCLUDES)
 endif
 
-libutil_unittests_la_LIBADD  = $(top_builddir)/src/lib/util/libb10-util.la
-libutil_unittests_la_LIBADD += $(top_builddir)/src/lib/util/io/libb10-util-io.la
+libutil_unittests_la_LIBADD  = $(top_builddir)/src/lib/util/io/libb10-util-io.la
 libutil_unittests_la_LIBADD += $(top_builddir)/src/lib/exceptions/libb10-exceptions.la
 
 CLEANFILES = *.gcno *.gcda