gui: rapidxml: Bail out if detecting ABX header

The parser is supposed to parse plain XMLs, ABX format is not yet supported.
Continuing to parse ABX XMLs would be spamming /tmp/recovery.log until triggering OOM.

Change-Id: I5c01045d6efef0b2ac497b40d78410c2b75d30d0
diff --git a/gui/rapidxml.hpp b/gui/rapidxml.hpp
index 33a8860..f47807d 100644
--- a/gui/rapidxml.hpp
+++ b/gui/rapidxml.hpp
@@ -1390,7 +1390,15 @@
             
             // Parse BOM, if any
             parse_bom<Flags>(text);
-            
+
+            // Abort if it's ABX format
+            if (text[0] == Ch('A') &&
+                text[1] == Ch('B') &&
+                text[2] == Ch('X')) {
+                RAPIDXML_PARSE_ERROR("ABX Format Unsupported by RapidXML", text);
+                return;
+            }
+
             // Parse children
             while (1)
             {