Remove allow_response_without_content

Let's just assume that no content type means no body.

BUG=25766813

Change-Id: I374f8769263e7772cc720826897b214e25f8f1d4
Reviewed-on: https://weave-review.googlesource.com/1827
Reviewed-by: Alex Vakulenko <avakulenko@google.com>

src/device_registration_info.cc

diff --git a/src/device_registration_info.cc b/src/device_registration_info.cc
index 6bd42bd..b29bd52 100644
--- a/src/device_registration_info.cc
+++ b/src/device_registration_info.cc
@@ -714,8 +714,8 @@
     return;
   }
 
-  if (data->allow_response_without_content &&
-      response->GetContentType().empty()) {
+  if (response->GetContentType().empty()) {
+    // Assume no body if no content type.
     cloud_backoff_entry_->InformOfRequest(true);
     return data->callback.Run({}, nullptr);
   }

src/device_registration_info.h

diff --git a/src/device_registration_info.h b/src/device_registration_info.h
index 5ba56a1..c196e0c 100644
--- a/src/device_registration_info.h
+++ b/src/device_registration_info.h
@@ -182,8 +182,6 @@
     provider::HttpClient::Method method;
     std::string url;
     std::string body;
-    // Workaround for inconsistent APIs which returns no body.
-    bool allow_response_without_content = false;
     CloudRequestDoneCallback callback;
   };
   void SendCloudRequest(const std::shared_ptr<const CloudRequestData>& data);