otcetera segfaults when killed with ^C

[bredelings]

This is not a big problem, since it just means the server isn't shutting down properly.

Here is a valgrind trace that might explain what the problem is:

2020-09-30 14:30:27,051 WARN  [default] Stopping service...
==477610== Invalid read of size 4
==477610==    at 0x1E8765: __exchange_and_add (atomicity.h:50)
==477610==    by 0x1E8765: __exchange_and_add_dispatch (atomicity.h:84)
==477610==    by 0x1E8765: _M_release (shared_ptr_base.h:155)
==477610==    by 0x1E8765: ~__shared_count (shared_ptr_base.h:733)
==477610==    by 0x1E8765: ~__shared_ptr (shared_ptr_base.h:1183)
==477610==    by 0x1E8765: std::shared_ptr<el::base::Storage>::~shared_ptr() (shared_ptr.h:121)
==477610==    by 0x5005B95: __cxa_finalize (cxa_finalize.c:83)
==477610==    by 0x4A2BE72: ??? (in /home/bredelings/Devel/OpenTree/otcetera/local/gcc-10/lib/x86_64-linux-gnu/libotcetera.so)
==477610==    by 0x4010342: _dl_fini (dl-fini.c:138)
==477610==    by 0x50055A6: __run_exit_handlers (exit.c:108)
==477610==    by 0x5005749: exit (exit.c:139)
==477610==    by 0x4FEDCD0: (below main) (libc-start.c:342)
==477610==  Address 0x535c778 is 8 bytes inside a block of size 24 free'd
==477610==    at 0x483A08B: operator delete(void*, unsigned long) (vg_replace_malloc.c:593)
==477610==    by 0x50055A6: __run_exit_handlers (exit.c:108)
==477610==    by 0x5005749: exit (exit.c:139)
==477610==    by 0x4FEDCD0: (below main) (libc-start.c:342)
==477610==  Block was alloc'd at
==477610==    at 0x4838DEF: operator new(unsigned long) (vg_replace_malloc.c:342)
==477610==    by 0x1CB930: __shared_count<el::base::Storage*> (shared_ptr_base.h:628)
==477610==    by 0x1CB930: __shared_count<el::base::Storage*> (shared_ptr_base.h:639)
==477610==    by 0x1CB930: __shared_ptr<el::base::Storage> (shared_ptr_base.h:1128)
==477610==    by 0x1CB930: shared_ptr<el::base::Storage> (shared_ptr.h:159)
==477610==    by 0x1CB930: __static_initialization_and_destruction_0 (tolwsbooting.cpp:19)
==477610==    by 0x1CB930: _GLOBAL__sub_I__ZN2el4base5utils13s_currentUserB5cxx11E (tolwsbooting.cpp:1371)
==477610==    by 0x28BA44: __libc_csu_init (in /home/bredelings/Devel/OpenTree/otcetera/local/gcc-10/bin/otc-tol-ws)
==477610==    by 0x4FEDC59: (below main) (libc-start.c:264)
==477610== 
==477610== 
==477610== HEAP SUMMARY:
==477610==     in use at exit: 158,914 bytes in 438 blocks
==477610==   total heap usage: 45,269 allocs, 44,831 frees, 2,753,594 bytes allocated
==477610== 
==477610== LEAK SUMMARY:
==477610==    definitely lost: 24 bytes in 1 blocks
==477610==    indirectly lost: 35,202 bytes in 428 blocks
==477610==      possibly lost: 320 bytes in 1 blocks
==477610==    still reachable: 123,368 bytes in 8 blocks
==477610==         suppressed: 0 bytes in 0 blocks
==477610== Rerun with --leak-check=full to see details of leaked memory
==477610== 
==477610== For lists of detected and suppressed errors, rerun with: -s
==477610== ERROR SUMMARY: 3 errors from 1 contexts (suppressed: 0 from 0)