config parsing does not abort if ServerTransportPlugin but no ORPort
``` Jul 03 00:42:52.632 [notice] Tor v0.2.3.12-alpha-dev (git-e1ac458802b3cd18) running on Linux x86_64. Jul 03 00:42:52.632 [notice] Tor can't help you if you use it wrong! Learn how to be safe at https://www.torproject.org/download/download#warning Jul 03 00:42:52.632 [notice] This version is not a stable Tor release. Expect more bugs than usual. Jul 03 00:42:52.638 [notice] Initialized libevent version 2.0.16-stable using method epoll (with changelist). Good. Jul 03 00:42:52.638 [notice] Opening Socks listener on 127.0.0.1:0 Jul 03 00:42:52.638 [notice] Socks listener listening on port 56396. Jul 03 00:42:52.000 [warn] You are running Tor as root. You don't need to, and you probably shouldn't. Jul 03 00:42:52.000 [notice] No AES engine found; using AES_* functions. Jul 03 00:42:52.000 [notice] This OpenSSL has a good implementation of counter mode; using it. Jul 03 00:42:52.000 [notice] OpenSSL OpenSSL 1.0.1 14 Mar 2012 looks like version 0.9.8m or later; I will try SSL_OP to enable renegotiation Jul 03 00:42:52.000 [notice] Reloaded microdescriptor cache. Found 2869 descriptors. Jul 03 00:42:52.000 [notice] I learned some more directory information, but not enough to build a circuit: We have no usable consensus. Program received signal SIGSEGV, Segmentation fault. 0x0000000000419510 in create_managed_proxy_environment (mp=0x7599e0) at transports.c:1191 1191 smartlist_add_asprintf(envs, "TOR_PT_ORPORT=127.0.0.1:%s", (gdb) bt full #0 0x0000000000419510 in create_managed_proxy_environment (mp=0x7599e0) at transports.c:1191 options = 0x757850 envs = 0x75d2b0 merged_env_vars = 0x8db6d0 env = <optimized out> #1 launch_managed_proxy (mp=0x7599e0) at transports.c:500 retval = <optimized out> env = 0x7fffffffe330 #2 configure_proxy (mp=0x7599e0) at transports.c:651 r = <optimized out> stdout_buf = "\f\000\000\000\000\000\000\000\000\274u\000\000\000\000\000\000\235u", '\000' <repeats 13 times>"\250, \346R", '\000' <repeats 14 times>"\235, u\000\000\000\000\000\000\274u\000\000\000\000\000\000\274u", '\000' <repeats 14 times>"\274, u\000$ #3 pt_configure_remaining_proxies () at transports.c:571 mp_sl_idx = <optimized out> mp_sl_len = <optimized out> mp = 0x7599e0 tmp = 0x78c4c0 __PRETTY_FUNCTION__ = "pt_configure_remaining_proxies" ```
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