Tor: Use of unitialized value in token_check_object (src/or/parsecommon.c:224)

Triggered in 22139c0, compiled with -fsanitize=memory and clang 6.0.0-trunk. ./fuzz-consensus test00d68 =9591==WARNING: MemorySanitizer: use-of-uninitialized-value 0 0x55ca86e51348 in tokencheckobject /root/tor/src/or/parsecommon.c:224:13 1 0x55ca86e51348 in getnexttoken...