Move rootwrap config files from etc/* into etc/glance/*

To cleanly utilize devstack's configure_rootwrap function to
install rootwrap config files, these should be placed in
etc/glance/ directory as nova and cinder do.

Change-Id: I6d4ee6929f3c3536424bb6790c958aa464860300

releasenotes/notes/move-rootwrap-config-f2cf435c548aab5c.yaml

@@ -0,0 +1,5 @@
+---
+upgrade:
+  - Packagers should be aware that the rootwrap configuration
+    files have been moved from etc/ to etc/glance/ in order to
+    be consistent with where other projects place these files.