dhcp: security bump to version 4.1-ESV-R6

Fixes CVE-2012-3571 and CVE-2012-3954.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/dhcp/dhcp.mk

@@ -4,7 +4,7 @@
 #
 #############################################################
 
-DHCP_VERSION  = 4.1-ESV-R4
+DHCP_VERSION  = 4.1-ESV-R6
 DHCP_SITE     = http://ftp.isc.org/isc/dhcp/$(DHCP_VERSION)
 DHCP_CONF_ENV = ac_cv_file__dev_random=yes
 DHCP_CONF_OPT = \