flame crashes on empty input file

[oerdnj]

On latest master:

$ git show HEAD
commit a5179dbc0d6df8468a29302734b344af5fc9f8e4 (HEAD -> master, origin/master, origin/HEAD)
Merge: b4c2ac5 64b40bc
Author: Shannon Weyrick <sweyrick@nsone.net>
Date:   Mon Feb 17 09:27:33 2020 -0500

    Merge pull request #30 from DNS-OARC/tcptls-to-dot

    Change "tcptls" to "dot", update documentation, bump version.

the flamethrower core dumps:

$ flame -f /dev/null localhost
binding to 0.0.0.0
flaming target(s) [127.0.0.1] on port 53 with 10 concurrent generators, each sending 10 queries every 1ms on protocol udp
query generator [file] contains 0 record(s)
Floating point exception (core dumped)

[weyrick]

Thanks @oerdnj, we'll look into it and get a fix up.