BUG/MEDIUM: dns: unbreak DNS resolver after header fix

DNS requests (using the internal resolver) are corrupted since commit
e2f84977165a ("BUG/MINOR: dns: fix DNS header definition").

Fix it by defining the struct in network byte order, while complying
with RFC 2535, section 6.1.

First reported by Eduard Vopicka on discourse.

This must be backported to 1.6 (1.6.5 is affected).
1 file changed