Remove getHasDns() and VirtualNetwork.mHasDns

getHasDns() and VirtualNetwork.mHasDns are no more useful after commit
aops/658122.

Bug: 116539103
Test: system/netd/tests/runtests.sh pass

Change-Id: Ica04984a954a9e89a5eb38a9b262775d686f8ed4
diff --git a/tests/binder_test.cpp b/tests/binder_test.cpp
index 77aae5d..5d1d874 100644
--- a/tests/binder_test.cpp
+++ b/tests/binder_test.cpp
@@ -546,8 +546,8 @@
     EXPECT_TRUE(mNetd->networkCreatePhysical(TEST_NETID1, INetd::PERMISSION_NONE).isOk());
     EXPECT_EQ(EEXIST, mNetd->networkCreatePhysical(TEST_NETID1, INetd::PERMISSION_NONE)
                               .serviceSpecificErrorCode());
-    EXPECT_EQ(EEXIST, mNetd->networkCreateVpn(TEST_NETID1, false, true).serviceSpecificErrorCode());
-    EXPECT_TRUE(mNetd->networkCreateVpn(TEST_NETID2, false, true).isOk());
+    EXPECT_EQ(EEXIST, mNetd->networkCreateVpn(TEST_NETID1, true).serviceSpecificErrorCode());
+    EXPECT_TRUE(mNetd->networkCreateVpn(TEST_NETID2, true).isOk());
 
     EXPECT_TRUE(mNetd->networkAddInterface(TEST_NETID1, sTun.name()).isOk());
     EXPECT_EQ(EBUSY,
@@ -562,8 +562,8 @@
 TEST_F(BinderTest, NetworkUidRules) {
     const uint32_t RULE_PRIORITY_SECURE_VPN = 12000;
 
-    EXPECT_TRUE(mNetd->networkCreateVpn(TEST_NETID1, false, true).isOk());
-    EXPECT_EQ(EEXIST, mNetd->networkCreateVpn(TEST_NETID1, false, true).serviceSpecificErrorCode());
+    EXPECT_TRUE(mNetd->networkCreateVpn(TEST_NETID1, true).isOk());
+    EXPECT_EQ(EEXIST, mNetd->networkCreateVpn(TEST_NETID1, true).serviceSpecificErrorCode());
     EXPECT_TRUE(mNetd->networkAddInterface(TEST_NETID1, sTun.name()).isOk());
 
     std::vector<UidRangeParcel> uidRanges = {makeUidRangeParcel(BASE_UID + 8005, BASE_UID + 8012),