Undo Utils dependency on VolumeManager

I want to use Utils in another executable, so breaking this link.

Bug: 25861755
Test: compiles (and boots, though that doesn't exercise changed code)
Change-Id: I6bb447453bb370fefb7f2f3aceb459428bdee6a7
diff --git a/Utils.h b/Utils.h
index 9163006..c5955cc 100644
--- a/Utils.h
+++ b/Utils.h
@@ -38,6 +38,9 @@
 extern security_context_t sFsckContext;
 extern security_context_t sFsckUntrustedContext;
 
+// TODO remove this with better solution, b/64143519
+extern bool sSleepOnUnmount;
+
 status_t CreateDeviceNode(const std::string& path, dev_t dev);
 status_t DestroyDeviceNode(const std::string& path);