SEGV in qdr_link_cleanup_deliveries_CT during system_tests_multi_tenancy

37: ASAN:SIGSEGV
37: =================================================================
37: ==14106==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7fd36213a988 bp 0x7fff4d586480 sp 0x7fff4d5862c0 T0)
37:     #0 0x7fd36213a987 in qdr_link_cleanup_deliveries_CT /home/travis/build/apache/qpid-dispatch/src/router_core/connections.c:864
37:     #1 0x7fd36219b36e in qdr_core_free /home/travis/build/apache/qpid-dispatch/src/router_core/router_core.c:228
37:     #2 0x7fd362213008 in qd_router_free /home/travis/build/apache/qpid-dispatch/src/router_node.c:2148
37:     #3 0x7fd3620a27a1 in qd_dispatch_free /home/travis/build/apache/qpid-dispatch/src/dispatch.c:371
37:     #4 0x401dd2 in main_process /home/travis/build/apache/qpid-dispatch/router/src/main.c:119
37:     #5 0x403917 in main /home/travis/build/apache/qpid-dispatch/router/src/main.c:369
37:     #6 0x7fd360a0a82f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
37:     #7 0x401ac8 in _start (/home/travis/build/apache/qpid-dispatch/build/router/qdrouterd+0x401ac8)
37: 
37: AddressSanitizer can not provide additional info.
37: SUMMARY: AddressSanitizer: SEGV /home/travis/build/apache/qpid-dispatch/src/router_core/connections.c:864 qdr_link_cleanup_deliveries_CT
37: ==14106==ABORTING