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/capabilities.h b/init/capabilities.h
index abd7fb2..ef507a6 100644
--- a/init/capabilities.h
+++ b/init/capabilities.h
@@ -20,6 +20,9 @@
 #include <bitset>
 #include <string>
 
+namespace android {
+namespace init {
+
 using CapSet = std::bitset<CAP_LAST_CAP + 1>;
 
 int LookupCap(const std::string& cap_name);
@@ -27,4 +30,7 @@
 unsigned int GetLastValidCap();
 bool SetCapsForExec(const CapSet& to_keep);
 
+}  // namespace init
+}  // namespace android
+
 #endif  // _INIT_CAPABILITIES_H