recovery_utils: Use libvoid_headers.

Test: mmm bootable/recovery
Change-Id: I2ad7620d0f967cb018a415358379c34804e232c5
diff --git a/recovery_utils/Android.bp b/recovery_utils/Android.bp
index 463f27f..1f42217 100644
--- a/recovery_utils/Android.bp
+++ b/recovery_utils/Android.bp
@@ -57,15 +57,16 @@
         "thermalutil.cpp",
     ],
 
+    header_libs: [
+        "libvold_headers",
+    ],
+
     export_include_dirs: [
         "include",
     ],
 
-    include_dirs: [
-        "system/vold",
-    ],
-
     export_static_lib_headers: [
+        // roots.h includes <fstab/fstab.h>.
         "libfstab",
     ],