MXS-2067: Fix build failures

The luafilter didn't include the <mutex> header and mqfilter used the
wrong lock type.

server/modules/filter/luafilter/luafilter.cc

@@ -43,6 +43,7 @@
 #include <lua.h>
 #include <lualib.h>
 #include <string.h>
+#include <mutex>
 #include <maxscale/alloc.h>
 #include <maxscale/filter.h>
 #include <maxscale/log.h>

server/modules/filter/mqfilter/mqfilter.cc

@@ -212,8 +212,8 @@ typedef struct
     int                     conn_stat;  /**state of the connection to the server*/
     int                     rconn_intv; /**delay for reconnects, in seconds*/
     time_t                  last_rconn; /**last reconnect attempt*/
-    std::mutex              rconn_lock;
-    std::mutex              msg_lock;
+    pthread_mutex_t         rconn_lock;
+    pthread_mutex_t         msg_lock;
     mqmessage*              messages;
     enum log_trigger_t      trgtype;
     SRC_TRIG*               src_trg;