app_rpt: crash when calling send_newkey

[InterLinked1]

Periodic crash on SCRN seems to be due to this:

==293080==
==293080== Warning: invalid file descriptor 2 in syscall write()
==293080==    Use --log-fd=<number> to select an alternative log fd.
==293080==
==293080== Process terminating with default action of signal 6 (SIGABRT): dumping core
==293080==    at 0x55D6CE1: raise (raise.c:51)
==293080==    by 0x55C0536: abort (abort.c:79)
==293080==    by 0x327D45: ast_do_crash (utils.c:2770)
==293080==    by 0x327DE4: __ast_assert_failed (utils.c:2799)
==293080==    by 0x184263: log_bad_ao2 (astobj2.c:219)
==293080==    by 0x1842C7: __ao2_lock (astobj2.c:224)
==293080==    by 0xDDBA212: send_newkey (rpt_channel.c:464)
==293080==    by 0xDDB212E: rpt_exec (app_rpt.c:6864)
==293080==    by 0x281D40: pbx_exec (pbx_app.c:492)
==293080==    by 0x26BD7B: pbx_extension_helper (pbx.c:2972)
==293080==    by 0x27006A: ast_spawn_extension (pbx.c:4227)
==293080==    by 0x270E0E: __ast_pbx_run (pbx.c:4401)
==293080==
==293080== HEAP SUMMARY:
==293080==     in use at exit: 39,186,771 bytes in 254,441 blocks
==293080==   total heap usage: 56,642,697 allocs, 56,388,256 frees, 24,917,630,646 bytes allocated
==293080==
==293080== LEAK SUMMARY:
==293080==    definitely lost: 897 bytes in 32 blocks
==293080==    indirectly lost: 0 bytes in 0 blocks
==293080==      possibly lost: 329,192 bytes in 12,511 blocks
==293080==    still reachable: 38,856,682 bytes in 241,898 blocks
==293080==                       of which reachable via heuristic:
==293080==                         length64           : 128,544 bytes in 290 blocks
==293080==         suppressed: 0 bytes in 0 blocks
==293080== Rerun with --leak-check=full to see details of leaked memory
==293080==
==293080== Use --track-origins=yes to see where uninitialised values come from
==293080== ERROR SUMMARY: 1555 errors from 29 contexts (suppressed: 0 from 0)

[InterLinked1]

From another crash on SCRN:

```==328788== Process terminating with default action of signal 6 (SIGABRT): dumping core
==328788==    at 0x55D6CE1: raise (raise.c:51)
==328788==    by 0x55C0536: abort (abort.c:79)
==328788==    by 0x327D45: ast_do_crash (utils.c:2770)
==328788==    by 0x1808FA: my_do_crash (astmm.c:230)
==328788==    by 0x181311: __ast_free (astmm.c:488)
==328788==    by 0xF9949EC: iax_frame_free (parser.c:1333)
==328788==    by 0xF945204: iax2_frame_free (chan_iax2.c:2141)
==328788==    by 0xF94AFBD: __attempt_transmit (chan_iax2.c:3633)
==328788==    by 0xF97A1CE: iax2_process_thread (chan_iax2.c:12187)
==328788==    by 0x324C53: dummy_start (utils.c:1574)
==328788==    by 0x527EEA6: start_thread (pthread_create.c:477)
==328788==    by 0x569AA2E: clone (clone.S:95)
==328788==
==328788== HEAP SUMMARY:
==328788==     in use at exit: 38,707,346 bytes in 253,703 blocks
==328788==   total heap usage: 100,912,127 allocs, 100,658,424 frees, 45,606,369,839 bytes allocated
==328788==
==328788== LEAK SUMMARY:
==328788==    definitely lost: 120 bytes in 1 blocks
==328788==    indirectly lost: 0 bytes in 0 blocks
==328788==      possibly lost: 326,720 bytes in 12,443 blocks
==328788==    still reachable: 38,380,506 bytes in 241,259 blocks
==328788==                       of which reachable via heuristic:
==328788==                         length64           : 128,544 bytes in 290 blocks
==328788==         suppressed: 0 bytes in 0 blocks
==328788== Rerun with --leak-check=full to see details of leaked memory