set display ooc caused crash

[ghost]

commit ab8ebd6

Setup:

Ubuntu 18 LTS with sipp client and server on same machine
Server setup: sipp -sn uas
Client setup: sipp -sn uac 127.0.0.1

Traffic was passing normally. I entered command mode (pressed "c") and then entered the command "set display ooc". The client core dumped. I repeated the crash with valgrind which produced the following dump:

==12081== at 0x18EEC7: screentask::report(bool) (in /usr/local/bin/sipp)
==12081== by 0x18EF5A: screentask::run() (in /usr/local/bin/sipp)
==12081== by 0x1C96DA: traffic_thread() (in /usr/local/bin/sipp)
==12081== by 0x1CE00B: main (in /usr/local/bin/sipp)
==12081== Address 0x68 is not stack'd, malloc'd or (recently) free'd
==12081==
==12081==
==12081== Process terminating with default action of signal 11 (SIGSEGV): dumping core
==12081== Access not within mapped region at address 0x68
==12081== at 0x18EEC7: screentask::report(bool) (in /usr/local/bin/sipp)
==12081== by 0x18EF5A: screentask::run() (in /usr/local/bin/sipp)
==12081== by 0x1C96DA: traffic_thread() (in /usr/local/bin/sipp)
==12081== by 0x1CE00B: main (in /usr/local/bin/sipp)
==12081== If you believe this happened as a result of a stack
==12081== overflow in your program's main thread (unlikely but
==12081== possible), you can try to increase the size of the
==12081== main thread stack using the --main-stacksize= flag.
==12081== The main thread stack size used in this run was 8388608.
==12081==
==12081== HEAP SUMMARY:
==12081== in use at exit: 204,000 bytes in 1,135 blocks
==12081== total heap usage: 5,328 allocs, 4,193 frees, 15,299,249 bytes allocated
==12081==
==12081== LEAK SUMMARY:
==12081== definitely lost: 0 bytes in 0 blocks
==12081== indirectly lost: 0 bytes in 0 blocks
==12081== possibly lost: 0 bytes in 0 blocks
==12081== still reachable: 204,000 bytes in 1,135 blocks
==12081== of which reachable via heuristic:
==12081== multipleinheritance: 7,008 bytes in 73 blocks
==12081== suppressed: 0 bytes in 0 blocks
==12081== Rerun with --leak-check=full to see details of leaked memory
==12081==
==12081== For counts of detected and suppressed errors, rerun with: -v
==12081== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
Segmentation fault (core dumped)