Fix parsing of unknown directives in resolv.conf

Fix parsing of unknown directives in resolv.conf

Only call eatline() to skip to the next line if we're not
already at the end of a line when parsing an unknown directive.
We were accidentally skipping the next line when there was only
a single unknown directive on the current line.

(cherry picked from commit eb78ad20803b28f1a5ede52115ad6bd73cfeb843)