Fix build.

Missing a #define to map android_atomic_swap to its new name.  Worked
fine in the other branches, because nobody was using android_atomic_swap
in the other branches.

Change-Id: I0e730e9823ac5cd2fee5a3f856ce05d36df5d87e
diff --git a/include/cutils/atomic.h b/include/cutils/atomic.h
index 0200709..4979c8a 100644
--- a/include/cutils/atomic.h
+++ b/include/cutils/atomic.h
@@ -121,6 +121,7 @@
  */
 #define android_atomic_write android_atomic_release_store
 #define android_atomic_cmpxchg android_atomic_release_cas
+#define android_atomic_swap android_atomic_release_swap
 
 #ifdef __cplusplus
 } // extern "C"