user_mgmt: Fix SEGV on 64bit

The password management code takes a file off disk and interprets it
as a C struct. This is neither endian safe, 32/64 bit safe nor safe
against C struct alignment rules.

Fix the SEGV on 64bit by switching from size_t to uint32_t.

Signed-off-by: Anton Blanchard <anton@ozlabs.org>
Change-Id: Ibabd947284441ec141a9d2d3800f1ae95a0a7906
diff --git a/user_channel/passwd_mgr.cpp b/user_channel/passwd_mgr.cpp
index 9b232b5..e2bd28a 100644
--- a/user_channel/passwd_mgr.cpp
+++ b/user_channel/passwd_mgr.cpp
@@ -51,11 +51,11 @@
 {
     char signature[10];
     unsigned char reseved[2];
-    size_t hashSize;
-    size_t ivSize;
-    size_t dataSize;
-    size_t padSize;
-    size_t macSize;
+    uint32_t hashSize;
+    uint32_t ivSize;
+    uint32_t dataSize;
+    uint32_t padSize;
+    uint32_t macSize;
 };
 
 using namespace phosphor::logging;