Revert "Align MetaPassStruct for cross-arch consistency"

This patch broke the upgrade for 32-bit systems. Any system with an
existing password file won't be able to use the same password file
after this upgrade. We need to implement a backward-compatible fix in
the phosphor-host-ipmid repository.

This reverts commit 1241052b53be928fed70c33a03ad5a99d51e8ffa.

Change-Id: I1124f291265858d7a8015f25c79401483dbb45d6
Signed-off-by: George Liu <liuxiwei@ieisystem.com>
diff --git a/user_channel/passwd_mgr.cpp b/user_channel/passwd_mgr.cpp
index 6e515da..929a83c 100644
--- a/user_channel/passwd_mgr.cpp
+++ b/user_channel/passwd_mgr.cpp
@@ -51,7 +51,7 @@
 struct MetaPassStruct
 {
     char signature[10];
-    unsigned char reseved[6];
+    unsigned char reseved[2];
     size_t hashSize;
     size_t ivSize;
     size_t dataSize;
@@ -534,8 +534,7 @@
     OPENSSL_cleanse(key.data(), keyLen);
 
     // Update the meta password structure.
-    MetaPassStruct metaData = {
-        META_PASSWD_SIG, {0, 0, 0, 0, 0, 0}, 0, 0, 0, 0, 0};
+    MetaPassStruct metaData = {META_PASSWD_SIG, {0, 0}, 0, 0, 0, 0, 0};
     metaData.hashSize = hashLen;
     metaData.ivSize = ivLen;
     metaData.dataSize = bytesWritten;