XMLParser: Simplify the code in func _handleParseResult() -> Bool.

Author: YOCKOW

Foundation/XMLParser.swift

@@ -465,18 +465,14 @@ open class XMLParser : NSObject {
     }
 
     internal func _handleParseResult(_ parseResult: Int32) -> Bool {
-        var result = true
-        if parseResult != 0 {
-            if parseResult != -1 {
-                // TODO: determine if this result is a fatal error from libxml via the CF implementations
-            }
-            
+        if parseResult == 0 {
+            return true
+        } else {
             if _parserError == nil {
                 _parserError = NSError(domain: XMLParser.errorDomain, code: Int(parseResult))
             }
-            result = false
         }
-        return result
+        return false
     }
 
     internal func parseData(_ data: Data) -> Bool {