Merge #1891

1891: Reinit the dns lib before each call r=karknu a=karknu

The dns library only reads /etc/resolv.conf once which means that inorder to
cope with changing networks conditions we need to reinit the library
before each use.

Workaround for the bug reported in IntersectMBO/cardano-node#731 

Co-authored-by: Karl Knutsson <[email protected]>
Co-authored-by: Marcin Szamotulski <[email protected]>