Add the ability to revert a crypto mapping when unmounting a volume

Add the force_and_revert option to the unmount command which will force
the unmount, and revert a crypto mapping.  This is used during factory
reset so that when the internal sdcard volume is formatted, it formats
the raw device, not the encrypted mapping.

Change-Id: I36b6ff9bb54863b121de635472a303bf4a2334a9
diff --git a/VolumeManager.h b/VolumeManager.h
index caa0b62..a000556 100644
--- a/VolumeManager.h
+++ b/VolumeManager.h
@@ -79,7 +79,7 @@
 
     int listVolumes(SocketClient *cli);
     int mountVolume(const char *label);
-    int unmountVolume(const char *label, bool force);
+    int unmountVolume(const char *label, bool force, bool revert);
     int shareVolume(const char *label, const char *method);
     int unshareVolume(const char *label, const char *method);
     int shareEnabled(const char *path, const char *method, bool *enabled);