xenmon: close qos_fd when finished with it in alloc_qos_data

Otherwise the fd is leaked. NB the mmap'd memory in the global
cpu_qos_data[n] is not affected by closing the underlying fd.

Compile tested only.

CID: 1055930

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>

tools/xenmon/xenbaked.c

@@ -689,6 +689,7 @@ static void alloc_qos_data(int ncpu)
         cpu_qos_data[n] = new_qos;
     }
     free(dummy);
+    close(qos_fd);
     new_qos = NULL;
 }