Use correct return value of dbe_read

dbe_read does not return http error code. It just returns a boolean ok/fail and result.
We were trying to unpack it into error code and message. Instead, use 404 error code and read_result as message to return proper error to the caller.

Change-Id: I2ed97cbad6b2def7df8de01bb8bfa23979cc5282
Closes-Bug: 1392643
Merge "Use correct return value of dbe_read"