MXS-2197: Make config.h and service.h C++ headers

This is the first step into converting the other headers into C++.

server/core/test/test_dcb.cc

@@ -34,7 +34,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include <maxscale/config.h>
+#include <maxscale/config.hh>
 #include <maxscale/listener.h>
 #include <maxscale/routingworker.hh>
 

server/core/test/test_local_address.cc

@@ -14,7 +14,7 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <iostream>
-#include <maxscale/config.h>
+#include <maxscale/config.hh>
 #include <maxscale/mysql_utils.h>
 
 using namespace std;

server/core/test/test_poll.cc

@@ -35,7 +35,7 @@
 #include <errno.h>
 #include <maxscale/dcb.h>
 #include <maxscale/listener.h>
-#include <maxscale/service.h>
+#include <maxscale/service.hh>
 
 #include "test_utils.h"
 

server/core/test/test_utils.h

@@ -20,7 +20,7 @@
 #include <maxscale/housekeeper.h>
 #include <maxscale/maxscale_test.h>
 #include <maxscale/log.h>
-#include <maxscale/config.h>
+#include <maxscale/config.hh>
 #include <maxscale/query_classifier.h>
 #include <maxscale/paths.h>
 #include <maxscale/alloc.h>