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/PhysicalNetwork.cpp b/server/PhysicalNetwork.cpp
index ee0e7c7..ccac323 100644
--- a/server/PhysicalNetwork.cpp
+++ b/server/PhysicalNetwork.cpp
@@ -22,6 +22,9 @@
 #define LOG_TAG "Netd"
 #include "log/log.h"
 
+namespace android {
+namespace net {
+
 namespace {
 
 WARN_UNUSED_RESULT int addToDefault(unsigned netId, const std::string& interface,
@@ -188,3 +191,6 @@
     mInterfaces.erase(interface);
     return 0;
 }
+
+}  // namespace net
+}  // namespace android