util: remove outdated comment from virLogFormatString

Introduced by commit 72ab0b6d which
added some code depending on libvirt's log format string into
qemuProcessReadLogOutput. This function was deleted by commit
932534e8 later.

Drop the comment.
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Closes: https://gitlab.com/libvirt/libvirt/-/issues/35

src/util/virlog.c

@@ -421,13 +421,6 @@ virLogFormatString(char **msg,
                    virLogPriority priority,
                    const char *str)
 {
-    /*
-     * Be careful when changing the following log message formatting, we rely
-     * on it when stripping libvirt debug messages from qemu log files. So when
-     * changing this, you might also need to change the code there.
-     * virLogFormatString() function name is mentioned there so it's sufficient
-     * to just grep for it to find the right place.
-     */
     if ((funcname != NULL)) {
         *msg = g_strdup_printf("%llu: %s : %s:%d : %s\n",
                                virThreadSelfID(), virLogPriorityString(priority),