Shorten the namespace and re-normalize include guards.

Change-Id: I93af4c1f19edf31098abd20ded1fcca6c5d83854
diff --git a/src/globals.h b/src/globals.h
index 2f85270..92d0cf7 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -5,8 +5,7 @@
 
 #include <stdint.h>
 
-namespace android {
-namespace runtime {
+namespace art {
 
 typedef uint8_t byte;
 typedef intptr_t word;
@@ -32,6 +31,6 @@
 const int kBitsPerWord = kWordSize * kBitsPerWord;
 const int kBitsPerInt = kIntSize * kBitsPerByte;
 
-} }  // namespace android::runtime
+}  // namespace art
 
 #endif  // ART_SRC_GLOBALS_H_