[1239] lo/lo0 interface detection fix in DHCPv4/DHCPv6 server tests.

src/bin/dhcp4/tests/dhcp4_srv_unittest.cc

@@ -56,9 +56,13 @@ public:
 class Dhcpv4SrvTest : public ::testing::Test {
 public:
     Dhcpv4SrvTest() {
-        unlink(INTERFACE_FILE);
+       unlink(INTERFACE_FILE);
         fstream fakeifaces(INTERFACE_FILE, ios::out|ios::trunc);
-        fakeifaces << "lo ::1";
+        if (if_nametoindex("lo")>0) {
+            fakeifaces << "lo ::1";
+        } else if (if_nametoindex("lo0")>0) {
+            fakeifaces << "lo0 ::1";
+        }
         fakeifaces.close();
     }
 

src/bin/dhcp6/tests/dhcp6_srv_unittest.cc

@@ -53,9 +53,12 @@ public:
     Dhcpv6SrvTest() {
         unlink(INTERFACE_FILE);
         fstream fakeifaces(INTERFACE_FILE, ios::out|ios::trunc);
-        fakeifaces << "lo ::1";
+        if (if_nametoindex("lo")>0) {
+            fakeifaces << "lo ::1";
+        } else if (if_nametoindex("lo0")>0) {
+            fakeifaces << "lo0 ::1";
+        }
         fakeifaces.close();
-
     }
     ~Dhcpv6SrvTest() {
         unlink(INTERFACE_FILE);