search_dns: Fixed missing type for target.
search_dns: Fixed missing type for target.

The parameter named 'target' did not have a type attribute, which
triggered a warning in the startup logs.

Reviewed-By: Gabor Gombas <3bb8c49439d9d044594e1c6967f991d0b4248a64@morganstanley.com>

quattor/aquilon,guillaume-philippon/aquilon,stdweird/aquilon,guillaume-philippon/aquilon,quattor/aquilon,guillaume-philippon/aquilon,stdweird/aquilon,quattor/aquilon,stdweird/aquilon