migrate more stuff from cdist-config to core/

Signed-off-by: Nico Schottelius <nico@kr.ethz.ch>

core/__cdist_usage

@@ -0,0 +1,27 @@
+#!/bin/sh
+#
+# 2011 Nico Schottelius (nico-cdist at schottelius.org)
+#
+# This file is part of cdist.
+#
+# cdist is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# cdist 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with cdist. If not, see <http://www.gnu.org/licenses/>.
+#
+#
+# Print error and exit (perror() alike)
+#
+
+__cdist_usage()
+{
+   __cdist_exit_err "$__cdist_myname: $@"
+}