Put most of netd into the android::net namespace.

Test: netd_{unit,integration}_test pass
Test: bullhead builds, boots
Bug: 34873832
Change-Id: I0a252328041b342f9c03cd08c11a69d452b045b3
diff --git a/server/Network.cpp b/server/Network.cpp
index f33cd88..eb2a233 100644
--- a/server/Network.cpp
+++ b/server/Network.cpp
@@ -22,6 +22,9 @@
 #include <android-base/strings.h>
 #include <sstream>
 
+namespace android {
+namespace net {
+
 Network::~Network() {
     if (!mInterfaces.empty()) {
         ALOGE("deleting network with netId %u without clearing its interfaces", mNetId);
@@ -86,3 +89,6 @@
 
 Network::Network(unsigned netId) : mNetId(netId) {
 }
+
+}  // namespace net
+}  // namespace android