Description of problem:
Since bug #437840 was fixed,
dhclient has known how to use dhcp.domain-search option sent by server,
but it doesn't request this option by default.

Steps to Reproduce:
1. Configure server to send domain-search option
echo 'option domain-search "sales.example.com", "example.com";' >> /etc/dhcp/dhcpd.conf
2. Start server
2. Start dhclient
  
Actual results:
Server doesn't send domain-search option because client doesn't request it.

Expected results:
1) Server sends defined domain-search option to client because client requests it.

Additional info:
man dhcp-options