Enable auto-encrypt drive at startup

Modify enablecrypto command to make the password optional. When it is
not there, default encrypt the device.

Remove a warning by making at least some parts of this file const-correct.

Bug: 11985952
Change-Id: Ie27da4c4072386d9d6519d97ff46c6dc4ed188dc
diff --git a/vdc.c b/vdc.c
index 210ef22..0a70bf7 100644
--- a/vdc.c
+++ b/vdc.c
@@ -59,7 +59,7 @@
             fprintf(stderr, "Error connecting (%s)\n", strerror(errno));
             exit(4);
         } else {
-          sleep(1);
+            sleep(1);
         }
     }