json_support: fix extra indenter

python/nomadcore/json_support.py

@@ -11,11 +11,11 @@ class ExtraIndenter(object):
         while True:
             j = val.find("\n", i)
             if j == -1:
-                fStream.write(val[i:])
+                self.fStream.write(val[i:])
                 return
             j += 1
-            fStream.write(val[i:j])
-            fStream.write(self.indent)
+            self.fStream.write(val[i:j])
+            self.fStream.write(self.indent)
             i = j
 
 def jsonCompactF(obj, fOut, check_circular = False):