util-lib: split out file attribute calls to chattr-util.[ch]

src/import/import-raw.c

@@ -25,6 +25,7 @@
 #include "sd-event.h"
 
 #include "btrfs-util.h"
+#include "chattr-util.h"
 #include "copy.h"
 #include "fd-util.h"
 #include "fileio.h"

src/import/pull-raw.c

@@ -26,6 +26,7 @@
 #include "sd-daemon.h"
 
 #include "btrfs-util.h"
+#include "chattr-util.h"
 #include "copy.h"
 #include "curl-util.h"
 #include "fd-util.h"