Fix: handle http500 response from shepherd

src/main/java/com/sheepit/client/Client.java

@@ -1090,7 +1090,12 @@ import okhttp3.HttpUrl;
 					// the client cannot recover from this error (it's server side config) so exit the retry loop
 					confirmJobReturnCode = Type.IMAGE_TOO_LARGE;
 					break retryLoop;
-					
+				
+				case ERROR_BAD_RESPONSE:
+					// set the error and retry on next loop
+					confirmJobReturnCode = Type.ERROR_BAD_UPLOAD_RESPONSE;
+					break;
+				
 				default:
 					// do nothing, try to do a request on the next loop
 					break;