deprecate(core): Add missing deprecation fields in processor

Author: ashwoods

Diff for: raven/processors.py

@@ -8,6 +8,7 @@
 from __future__ import absolute_import
 
 import re
+import warnings
 
 from raven.utils.compat import string_types, text_type, PY3
 from raven.utils import varmap
@@ -167,6 +168,16 @@ class SanitizePasswordsProcessor(SanitizeKeysProcessor):
     def sanitize_keys(self):
         return self.KEYS
 
+    @property
+    def FIELDS(self):
+        warnings.warn(
+            "`SanitizePasswordsProcessor.Fields` has been deprecated. Use "
+            "`SanitizePasswordsProcessor.KEYS` or `SanitizePasswordsProcessor.sanitize_keys` "
+            "instead",
+            DeprecationWarning,
+        )
+        return self.KEYS
+
     def sanitize(self, item, value):
         value = super(SanitizePasswordsProcessor, self).sanitize(item, value)
         if isinstance(value, string_types) and self.VALUES_RE.match(value):