Prevent needless provider checks

- if a hosts DN is listed in ALLOWED_TO_POST, they will be
  allowed to POST regardless of whether they are listed as
  as a provider or not. So why not check ALLOWED_TO_POST
  first and avoid a potentially expensive provider check
- this changes preserves the fact that BANNED_FROM_POST
  overwrites both ALLOWED_TO_POST and any provider lists

api/views/CloudRecordView.py

@@ -152,15 +152,15 @@ def _signer_is_valid(self, signer_dn):
             self.logger.info("Host %s is banned.", signer)
             return False
 
+        if signer_dn in settings.ALLOWED_TO_POST:
+            self.logger.info("Host %s has special access.", signer)
+            return True
+
         if signer in self._get_indigo_providers():
             self.logger.info("Host %s is listed as an INDIGO provider.",
                              signer)
             return True
 
-        if signer_dn in settings.ALLOWED_TO_POST:
-            self.logger.info("Host %s has special access.", signer)
-            return True
-
         # If we have not returned already
         # then site must be invalid
         self.logger.info('Site is not found on list of providers')