Fix DNS search entry in /etc/resolv.conf

Commit 66d1235 added support for
resolving DNS names from initramfs, but only the DNS domain was
configured for the DNS search. The DHCP client also provides the
`DOMAINSEARCH` variable that should be used for searching if available,
because it can contain more than one domain.

Signed-off-by: Benjamin Drung <benjamin.drung@cloud.ionos.com>

components/9990-networking.sh

@@ -156,7 +156,6 @@ EOF
 			if [ -n "${DNSDOMAIN}" ]
 			then
 				echo "domain ${DNSDOMAIN}" > /etc/resolv.conf
-				echo "search ${DNSDOMAIN}" >> /etc/resolv.conf
 			fi
 
 			for i in ${IPV4DNS0} ${IPV4DNS1} ${IPV4DNS1} ${DNSSERVERS}
@@ -166,6 +165,14 @@ EOF
 					echo "nameserver $i" >> /etc/resolv.conf
 				fi
 			done
+
+			if [ -n "${DOMAINSEARCH}" ]
+			then
+				echo "search ${DOMAINSEARCH}" >> /etc/resolv.conf
+			elif [ -n "${DNSDOMAIN}" ]
+			then
+				echo "search ${DNSDOMAIN}" >> /etc/resolv.conf
+			fi
 		fi
 
 		# Check if we have a network device at all