Remove built in "triggers"

Originally, the idea was that clients would replicate "OS/tree"s from
a build server, but we'd run things like "ldconfig" on the client.
This was to allow adding e.g. the nVidia binary driver.

However, the triggers were the only thing in the system at the moment
that really had expected knowledge of the *contents* of the OS, like
the location of binaries.

For now, it's architecturally cleaner if we move the burden of
triggers to the tree builder (e.g. gnome-ostree or RPM).  Eventually
we may want OSTree to assist with this type of thing (perhaps
something like RPM %ghost), but this is the right thing to do now.

src/libostree/ostree-sysroot.h

@@ -1,39 +0,0 @@
-/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
- *
- * Copyright (C) 2011 Colin Walters <walters@verbum.org>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
- *
- * Author: Colin Walters <walters@verbum.org>
- */
-
-#ifndef _OSTREE_SYSROOT
-#define _OSTREE_SYSROOT
-
-#include "ostree-core.h"
-#include "ostree-types.h"
-
-G_BEGIN_DECLS
-
-const char *const* ostree_get_sysroot_environ (void);
-
-gboolean ostree_run_triggers_in_root (GFile                  *root,
-                                      GCancellable           *cancellable,
-                                      GError                **error);
-
-G_END_DECLS
-
-#endif