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/util_test.cpp b/init/util_test.cpp
index 4bb8a83..c16ab74 100644
--- a/init/util_test.cpp
+++ b/init/util_test.cpp
@@ -26,6 +26,9 @@
 
 using namespace std::literals::string_literals;
 
+namespace android {
+namespace init {
+
 TEST(util, ReadFile_ENOENT) {
     std::string s("hello");
     std::string err;
@@ -187,3 +190,6 @@
     std::string path3 = android::base::StringPrintf("%s/three/directories/deep", test_dir.path);
     EXPECT_TRUE(is_dir(path1.c_str()));
 }
+
+}  // namespace init
+}  // namespace android