init: create android::init:: namespace

With some small fixups along the way

Test: Boot bullhead
Test: init unit tests
Change-Id: I7beaa473cfa9397f845f810557d1631b4a462d6a
diff --git a/init/devices_test.cpp b/init/devices_test.cpp
index e1e4e49..57d8e0f 100644
--- a/init/devices_test.cpp
+++ b/init/devices_test.cpp
@@ -24,6 +24,9 @@
 
 using namespace std::string_literals;
 
+namespace android {
+namespace init {
+
 class DeviceHandlerTester {
   public:
     void TestGetSymlinks(const std::string& platform_device, const Uevent& uevent,
@@ -400,3 +403,6 @@
     EXPECT_EQ(0U, permissions.uid());
     EXPECT_EQ(1001U, permissions.gid());
 }
+
+}  // namespace init
+}  // namespace android