Use standard RNG

The custom random number generator can now be replaced with a C++11
RNG. This greatly improves the reliability and trustworthiness of it.

In addition to this, the conversion of the RNG to a thread-local object
removes the race condition that was present in the previous
implementation. It also theoretically improves performance by a tiny bit.

server/modules/routing/avrorouter/avro.cc

@@ -35,7 +35,7 @@
 #include <maxscale/modulecmd.h>
 #include <maxscale/paths.h>
 #include <maxscale/protocol/mysql.h>
-#include <maxscale/random_jkiss.h>
+#include <maxscale/random.h>
 #include <maxscale/router.h>
 #include <maxscale/server.h>
 #include <maxscale/service.h>

server/modules/routing/avrorouter/avro_main.cc

@@ -30,7 +30,7 @@
 #include <maxscale/modulecmd.h>
 #include <maxscale/paths.h>
 #include <maxscale/protocol/mysql.h>
-#include <maxscale/random_jkiss.h>
+#include <maxscale/random.h>
 #include <maxscale/router.h>
 #include <maxscale/server.h>
 #include <maxscale/service.h>