Make tox-bootstrapd free memory on SIGINT and SIGTERM

[nurupo]

Useful for using memory analyzing tools.

Closes #1220

sed -i 's/DMIN_LOGGER_LEVEL/DMIN_LOGGER_LEVEL_IGNORE/' CMakeLists.txt
mkdir _build
cd _build
cmake -DBOOTSTRAP_DAEMON=ON \
      -DBUILD_TOXAV=OFF \
      -DENABLE_STATIC=ON \
      -DENABLE_SHARED=OFF \
      -DCMAKE_BUILD_TYPE=Debug \
      ..
make
cp ../other/bootstrap_daemon/tox-bootstrapd.conf .
sed -i "s|/var/lib/tox-bootstrapd|${PWD}|" tox-bootstrapd.conf
sed -i "s|/var/run/tox-bootstrapd|${PWD}|" tox-bootstrapd.conf
sed -i '/^bootstrap_nodes = /,$d' tox-bootstrapd.conf
python3 ../other/bootstrap_daemon/docker/get-nodes.py >> tox-bootstrapd.conf
valgrind --leak-check=full --show-leak-kinds=all \
         ./tox-bootstrapd --foreground --config tox-bootstrapd.conf

==13673== Memcheck, a memory error detector
==13673== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==13673== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==13673== Command: ./tox-bootstrapd --foreground --config tox-bootstrapd.conf
==13673== 
^C==13673== 
==13673== HEAP SUMMARY:
==13673==     in use at exit: 0 bytes in 0 blocks
==13673==   total heap usage: 2,801 allocs, 2,801 frees, 9,422,380 bytes allocated
==13673== 
==13673== All heap blocks were freed -- no leaks are possible
==13673== 
==13673== For counts of detected and suppressed errors, rerun with: -v
==13673== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

---

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[codecov]

Codecov Report

Merging #1221 into master will decrease coverage by 0.2%.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           master   #1221     +/-   ##
========================================
- Coverage    83.1%   82.8%   -0.3%     
========================================
  Files          82      82             
  Lines       14692   14647     -45     
========================================
- Hits        12214   12137     -77     
- Misses       2478    2510     +32

Impacted Files	Coverage Δ
toxcore/TCP_server.c	75.9% <0%> (-4.4%)	⬇️
toxcore/LAN_discovery.c	83% <0%> (-2.9%)	⬇️
toxcore/friend_connection.c	93.6% <0%> (-0.9%)	⬇️
toxcore/Messenger.c	86.5% <0%> (-0.7%)	⬇️
toxcore/DHT.c	76.6% <0%> (-0.2%)	⬇️
toxcore/onion_client.c	95.9% <0%> (-0.1%)	⬇️
toxcore/net_crypto.c	94.7% <0%> (ø)	⬆️
auto_tests/save_load_test.c	98.6% <0%> (+0.5%)	⬆️

---

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[iphydf]

@nurupo this needs rebase. Tests should pass now.

[nurupo]

Rebased.

[iphydf]

@nurupo again - appveyor was sad that day.

[nurupo]

Sure, rebased.