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/reboot.h b/init/reboot.h
index b304b3c..e559540 100644
--- a/init/reboot.h
+++ b/init/reboot.h
@@ -19,6 +19,9 @@
 
 #include <string>
 
+namespace android {
+namespace init {
+
 /* Reboot / shutdown the system.
  * cmd ANDROID_RB_* as defined in android_reboot.h
  * reason Reason string like "reboot", "userrequested"
@@ -32,4 +35,7 @@
 // Parses and handles a setprop sys.powerctl message.
 bool HandlePowerctlMessage(const std::string& command);
 
+}  // namespace init
+}  // namespace android
+
 #endif