Support for decrypted volumes

Wow! Such support! Many amaze decrypted!
...
Seriously, when the volume is in the `decrypted' state, there's no key
yet, but the metadata already are present so an NTFS reader can't mount
the volume.

src/dislocker.c

@@ -228,9 +228,16 @@ int main(int argc, char** argv)
 	if(get_dataset(bl_metadata, &dataset) != TRUE)
 	{
 		xprintf(L_CRITICAL, "Unable to find a valid dataset. Abort.\n");
+		ret = EXIT_FAILURE;
 		goto FIRST_CLEAN;
 	}
 	
+	/*
+	 * If the state of the volume is currently decrypted, there's no key to grab
+	 */
+	if(((bitlocker_header_t*)bl_metadata)->curr_state == DECRYPTED)
+		goto FIRST_CLEAN;
+	
 	/*
 	 * First, get the VMK datum using either a clear key, a recovery password
 	 * or a bek file

src/metadata/metadata.c

@@ -368,6 +368,11 @@ int check_state(bitlocker_header_t* metadata)
 				next_state
 			);
 			break;
+		case DECRYPTED:
+			xprintf(L_WARNING,
+				"The disk is about to get encrypted. Don't use " PROGNAME " if "
+				"you're willing to do so, this may corrupt your data."
+			);
 	}
 	
 	return TRUE;