Compiler warning in IfaceMgr unit tests

Minor and annoying but should be cleaned up. Compiling under Centos 7.5/gcc g++ (GCC) 4.8.5:

cc' || echo './'`option6_iaaddr_unittest.cc
In file included from /opt/googletest-release-1.8.0/googletest/include/gtest/gtest.h:58:0,
                 from ../../../../src/lib/dhcp/tests/pkt_filter6_test_utils.h:13,
                 from iface_mgr_unittest.cc:16:
/opt/googletest-release-1.8.0/googletest/include/gtest/internal/gtest-internal.h: In function ‘void {anonymous}::IfaceMgrTest::_ZN12_GLOBAL__N_112IfaceMgrTest25purgeExternalSockets4TestEb.isra.474(bool)’:
/opt/googletest-release-1.8.0/googletest/include/gtest/internal/gtest-internal.h:1188:3: warning: ‘queue_enabled’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   if (const ::testing::AssertionResult gtest_ar_ = \
   ^
iface_mgr_unittest.cc:684:18: note: ‘queue_enabled’ was declared here
             bool queue_enabled;
                  ^
In file included from /opt/googletest-release-1.8.0/googletest/include/gtest/gtest.h:58:0,
                 from ../../../../src/lib/dhcp/tests/pkt_filter6_test_utils.h:13,
                 from iface_mgr_unittest.cc:16:
/opt/googletest-release-1.8.0/googletest/include/gtest/internal/gtest-internal.h: In function ‘void {anonymous}::IfaceMgrTest::_ZN12_GLOBAL__N_112IfaceMgrTest25purgeExternalSockets6TestEb.isra.475(bool)’:
/opt/googletest-release-1.8.0/googletest/include/gtest/internal/gtest-internal.h:1188:3: warning: ‘queue_enabled’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   if (const ::testing::AssertionResult gtest_ar_ = \
   ^
iface_mgr_unittest.cc:767:18: note: ‘queue_enabled’ was declared here
             bool queue_enabled;
                  ^