rare memory leak in basic-sessionbreak-vg.sh

[alorbach]

There appears to be a possible memory leak in the basic-sessionbreak-vg.sh test that occurs from time to time.
Here is a sample report: https://build.rsyslog.com/#/builders/52/builds/469/steps/10/logs/test-suite_log

==44171== HEAP SUMMARY:
==44171== in use at exit: 32 bytes in 1 blocks
==44171== total heap usage: 70,282 allocs, 70,281 frees, 2,841,040 bytes allocated
==44171==
==44171== 32 bytes in 1 blocks are definitely lost in loss record 1 of 1
==44171== at 0x4C2B200: calloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==44171== by 0x4E3856D: addToEpollSet (relp.c:101)
==44171== by 0x4E38C56: addSessToEpoll (relp.c:147)
==44171== by 0x4E38C56: relpEngineAddToSess (relp.c:211)
==44171== by 0x4E38C56: handleConnectionRequest (relp.c:675)
==44171== by 0x4E38C56: engineEventLoopRun (relp.c:849)
==44171== by 0x4E392EE: relpEngineRun (relp.c:1029)
==44171== by 0x401F4E: main (receive.c:475)
==44171==
{
<insert_a_suppression_name_here>
Memcheck:Leak
match-leak-kinds: definite
fun:calloc
fun:addToEpollSet
fun:addSessToEpoll
fun:relpEngineAddToSess
fun:handleConnectionRequest
fun:engineEventLoopRun
fun:relpEngineRun
fun:main
}

[alorbach]

duplicated issue, see #192