libinstall: correct signature

Change-Id: I003c77cc41703ca0a1c595d77ae98e34ec3f9dca
diff --git a/install/wipe_data.cpp b/install/wipe_data.cpp
index 387abae..2ae4993 100755
--- a/install/wipe_data.cpp
+++ b/install/wipe_data.cpp
@@ -100,7 +100,7 @@
   // ui->SetBackground(RecoveryUI::ERASING);
   // ui->SetProgressType(RecoveryUI::INDETERMINATE);
 
-  bool success = EraseVolume("/cache", nullptr, false);
+  bool success = EraseVolume("/cache", false);
   // ui->Print("Cache wipe %s.\n", success ? "complete" : "failed");
   return success;
 }