sync: rename sync/sync.h to android/sync.h

Leave a temporary symlink from the old name to avoid having to change
all dependencies simultaneously.

Bug: 1901466
Test: m
Change-Id: Id210f0091457e52e1a6e048d241a723bdbe8779b
diff --git a/libsync/sync.c b/libsync/sync.c
index e68cc89..27dab83 100644
--- a/libsync/sync.c
+++ b/libsync/sync.c
@@ -27,7 +27,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
-#include <sync/sync.h>
+#include <android/sync.h>
 
 /* Legacy Sync API */