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/init.h b/init/init.h
index 6725a70..479b771 100644
--- a/init/init.h
+++ b/init/init.h
@@ -19,6 +19,11 @@
 
 #include <string>
 
+#include <selinux/label.h>
+
+namespace android {
+namespace init {
+
 // Note: These globals are *only* valid in init, so they should not be used in ueventd,
 // watchdogd, or any files that may be included in those, such as devices.cpp and util.cpp.
 // TODO: Have an Init class and remove all globals.
@@ -39,4 +44,7 @@
 
 void DumpState();
 
+}  // namespace init
+}  // namespace android
+
 #endif  /* _INIT_INIT_H */