Merge #10056: [zmq] Call va_end() on va_start()ed args.

Summary:
5ba61f0 [zmq] Call va_end() on va_start()ed args. (Karl-Johan Alm)

Tree-SHA512: fbd3a0c29308ca9607f362f14fa7ea9c949a3f25dc09a349fe3b3ffd316b573c86778e29d3b9d55c684571eacae50aca90bb872e2e5489818d0af8310511fe79

Backport Core PR10056
https://github.com/bitcoin/bitcoin/pull/10056/files

Test Plan:

make check
test_runner.py interface_zmq

Reviewers: deadalnix, Fabien, markblundeberg, #bitcoin_abc

Reviewed By: deadalnix, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D3145