Update the mechanism used to keep track of what kind of syncing to do for

WAL transaction commits and checkpoint operations.  Use the checkpoint-style
of syncing to sync the header of a new or restarted WAL file.

FossilOrigin-Name: bf65dae8d4297c57ac63228ccf0100f9fabf2fb600438c9f2e10a29c4b118168

src/os.c

@@ -98,7 +98,7 @@ int sqlite3OsTruncate(sqlite3_file *id, i64 size){
 }
 int sqlite3OsSync(sqlite3_file *id, int flags){
   DO_OS_MALLOC_TEST(id);
-  return id->pMethods->xSync(id, flags);
+  return flags ? id->pMethods->xSync(id, flags) : SQLITE_OK;
 }
 int sqlite3OsFileSize(sqlite3_file *id, i64 *pSize){
   DO_OS_MALLOC_TEST(id);