Make crow pretty print json responses

While not ideal for a real deployment, making crow "pretty print" the
json values aids in debug, and only introduces a mild performance
degredation.

TestedBy: checking /redfish/v1/ and verifying that it publishes
correctly

Change-Id: I9dbaa3a0500ef762ef4408852511b0e9b74cbd1f
Signed-off-by: Ed Tanous <ed.tanous@intel.com>
diff --git a/crow/include/crow/http_connection.h b/crow/include/crow/http_connection.h
index 87fa874..5cbe6ad 100644
--- a/crow/include/crow/http_connection.h
+++ b/crow/include/crow/http_connection.h
@@ -374,7 +374,7 @@
 
     if (res.body.empty() && !res.json_value.empty()) {
       res.json_mode();
-      res.body = res.json_value.dump();
+      res.body = res.json_value.dump(4);
     }
 
     if (!statusCodes.count(res.code)) {