replace defer by try/finally to avoid 0.19.6 compiler bug (#15)

serialization.nim

@@ -89,11 +89,7 @@ template loadFile*(Format: distinct type,
                    params: varargs[untyped]): auto =
   mixin init, ReaderType
   var stream = openFile(filename)
-  defer:
-    # TODO: destructors
-    if not stream.isNil:
-      stream[].close()
-
+  try:
     # TODO:
     # Remove this when statement once the following bug is fixed:
     # https://github.com/nim-lang/Nim/issues/9996
@@ -103,6 +99,10 @@ template loadFile*(Format: distinct type,
       var reader = init(ReaderType(Format), stream)
 
     reader.readValue(RecordType)
+  finally:
+    # TODO: destructors
+    if not stream.isNil:
+      stream[].close()
 
 template loadFile*[RecordType](Format: type,
                                filename: string,