Automatically detect /datadata from recovery.fstab. Remove BOARD_HAS_DATADATA.

Change-Id: I28d3c7a6beaacd77c67c5af0ae3464acfd2572e3
diff --git a/recovery.c b/recovery.c
index bf0575a..e1641c0 100644
--- a/recovery.c
+++ b/recovery.c
@@ -680,9 +680,9 @@
     device_wipe_data();
     erase_volume("/data");
     erase_volume("/cache");
-#ifdef BOARD_HAS_DATADATA
-    erase_volume("/datadata");
-#endif
+    if (has_datadata()) {
+        erase_volume("/datadata");
+    }
     erase_volume("/sd-ext");
     erase_volume("/sdcard/.android_secure");
     ui_print("Data wipe complete.\n");