egl/x11: Free memory allocated for reply structures on error

egl/x11: Free memory allocated for reply structures on error

This patch fixes memory leaks when reply is allocated and is not freed
on error execution path.

Found by enabling address sanitizer on simple EGL app.

```c

int main()
{
    EGLDisplay display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
    EGLint major;
    EGLint minor;

    if (!eglInitialize(display, &major, &minor))
    {
        return 1;
    }
    eglTerminate(display);
    return 0;
}
```

Compiled with: `gcc testme.c -o testme -fsanitize=address -lasan -lEGL`

Execution environment:
- Windows 10, VMWare Player 15.5.2 build-15785246 without 3D accelaration
- Guest OS: OpenSUSE Leap 15.2
- Mesa 19.3.4

Program output:

```sh
ASAN_OPTIONS=fast_unwind_on_malloc=0 ./testme

libEGL warning: DRI2: failed to authenticate
==52510==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 32 byte(s) in 1 object(s) allocated from:
    #0 0x7fa62315f500 in malloc (/usr/lib64/libasan.so.4+0xdc500)
    #1 0x7fa61e12d86b  (/usr/lib64/libxcb.so.1+0xf86b)
    #2 0x7fa61e12b5c7  (/usr/lib64/libxcb.so.1+0xd5c7)
    #3 0x7fa61e12cc3e  (/usr/lib64/libxcb.so.1+0xec3e)
    #4 0x7fa61e12cd4f in xcb_wait_for_reply (/usr/lib64/libxcb.so.1+0xed4f)
    #5 0x7fa61ebe02a5  (/usr/lib64/libEGL_mesa.so.0+0x202a5)
    #6 0x7fa61ebdb5ca  (/usr/lib64/libEGL_mesa.so.0+0x1b5ca)
    #7 0x7fa61ebd750c  (/usr/lib64/libEGL_mesa.so.0+0x1750c)
    #8 0x7fa61ebd7554  (/usr/lib64/libEGL_mesa.so.0+0x17554)
    #9 0x7fa61ebd1107  (/usr/lib64/libEGL_mesa.so.0+0x11107)
    #10 0x400856 in main (/home/user/testme+0x400856)
    #11 0x7fa622ad8349 in __libc_start_main (/lib64/libc.so.6+0x24349)
    #12 0x4006e9 in _start (/home/user/testme+0x4006e9)

SUMMARY: AddressSanitizer: 32 byte(s) leaked in 1 allocation(s).
```

Signed-off-by: Andrey Vostrikov <av.linux.dev@gmail.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Cc: mesa-stable
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6611>