Allow non datamedia devices to wipe encryption

With 5.0 L, we decrypt automatically if the default_password is
used. Non datamedia devices do not get the format data button so
they cannot wipe encryption off the device. This patch add a wipe
encryption button where the format data button would normally be
located on the Wipe page.

This patch also attempts to remove / delete the dm-crypt block
device before formatting.

Change-Id: I100d5d154d6c49254fd48e23279df973db5f23ae

partition.cpp

@@ -1371,6 +1371,15 @@ bool TWPartition::Wipe_Encryption() {
 
 	Has_Data_Media = false;
 	Decrypted_Block_Device = "";
+#ifdef TW_INCLUDE_CRYPTO
+	if (Is_Decrypted) {
+		if (!UnMount(true))
+			return false;
+		if (delete_crypto_blk_dev("userdata") != 0) {
+			LOGERR("Error deleting crypto block device, continuing anyway.\n");
+		}
+	}
+#endif
 	Is_Decrypted = false;
 	Is_Encrypted = false;
 	Find_Actual_Block_Device();
@@ -1381,6 +1390,7 @@ bool TWPartition::Wipe_Encryption() {
 			if (Mount(false))
 				PartitionManager.Add_MTP_Storage(MTP_Storage_ID);
 		}
+		DataManager::SetValue(TW_IS_ENCRYPTED, 0);
 #ifndef TW_OEM_BUILD
 		gui_print("You may need to reboot recovery to be able to use /data again.\n");
 #endif