libsysprof-capture: Stop defining G_LOG_DOMAIN

libsysprof-capture no longer calls any of the GLib logging functions
which make use of it.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Helps: #40

src/libsysprof-capture/sysprof-capture-reader.c

@@ -54,8 +54,6 @@
  * SPDX-License-Identifier: BSD-2-Clause-Patent
  */
 
-#define G_LOG_DOMAIN "sysprof-capture-reader"
-
 #include "config.h"
 
 #include <assert.h>