MD5 verification sanity

We can use switches and enums to make things more understandable
and work with results in a more sensible manner.

PS2: Move file MD5 verification and error handling into
     a separate function to reduce code.

PS3: Default to false in Check_Restore_File_MD5 function

Change-Id: Id3ee0bb444cf13be67bb5dec2c43f7c26a86b954
(cherry picked from commit 5c3950716e5c7c6279efd5f3f338d6d22e5215e2)
diff --git a/gui/theme/extra-languages/languages/zh_TW.xml b/gui/theme/extra-languages/languages/zh_TW.xml
index b7d6b1e..860b6cc 100644
--- a/gui/theme/extra-languages/languages/zh_TW.xml
+++ b/gui/theme/extra-languages/languages/zh_TW.xml
@@ -571,6 +571,7 @@
 		<string name="unable_resize">無法調整{1}大小。</string>
 		<string name="no_md5_found">未找到'{1}'MD5校驗檔案,請取消“啟用MD5校驗備份檔案”選項。</string>
 		<string name="md5_fail_match">'{1}' MD5校驗失敗。</string>
+		<string name="md5_matched">MD5 matched for '{1}'.</string>
 		<string name="fail_decrypt_tar">無法解密tar檔案:'{1}'</string>
 		<string name="format_data_msg">您可能需要重啟recovery才能使用/data。</string>
 		<string name="format_data_err">無法格式化並刪除加密。</string>