Fix a memory leak

Hello.

There is a memory leak when exiting xcb.
I'm using FreeBSD 13.
I don't know if memory leak occurs in Linux environment as well.

% more xcb.c 
#include <xcb/xcb.h>
#include <stdio.h>

int main ()
{
  xcb_connection_t *conn;

  conn = xcb_connect (NULL, NULL);

  if (xcb_connection_has_error (conn))
  {
    puts ("error");
    return 1;
  }

  xcb_disconnect (conn);

  return 0;
}

% valgrind --leak-check=full ./xcb
==7320== Memcheck, a memory error detector
==7320== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==7320== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==7320== Command: ./xcb
==7320== 
==7320== 
==7320== HEAP SUMMARY:
==7320==     in use at exit: 1,212 bytes in 3 blocks
==7320==   total heap usage: 21 allocs, 18 frees, 39,020 bytes allocated
==7320== 
==7320== 20 bytes in 1 blocks are definitely lost in loss record 1 of 3
==7320==    at 0x4851381: calloc (in /usr/local/libexec/valgrind/vgpreload_memcheck-amd64-freebsd.so)
==7320==    by 0x4897343: pthread_cond_init (in /lib/libthr.so.3)
==7320==    by 0x4873457: ??? (in /usr/local/lib/libxcb.so.1.1.0)
==7320==    by 0x4871E32: xcb_connect_to_fd (in /usr/local/lib/libxcb.so.1.1.0)
==7320==    by 0x4875C2E: xcb_connect_to_display_with_auth_info (in /usr/local/lib/libxcb.so.1.1.0)
==7320==    by 0x20199D: main (in /usr/home/hodong/projects/samples/xcb)
==7320== 
==7320== LEAK SUMMARY:
==7320==    definitely lost: 20 bytes in 1 blocks
==7320==    indirectly lost: 0 bytes in 0 blocks
==7320==      possibly lost: 0 bytes in 0 blocks
==7320==    still reachable: 1,192 bytes in 2 blocks
==7320==         suppressed: 0 bytes in 0 blocks
==7320== Reachable blocks (those to which a pointer was found) are not shown.
==7320== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==7320== 
==7320== For lists of detected and suppressed errors, rerun with: -s
==7320== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

I addad pthread_cond_destroy(&out->socket_cond);

And I changed the order in void _xcb_out_destroy(_xcb_out *out).

int _xcb_out_init(_xcb_out *out)
A
B
C

void _xcb_out_destroy(_xcb_out *out)
C
B
A