Fix could not find user glance on ensure files

commit 394661ec introduces a bug when the etc files ensure owner
'glance' run before the installation of the packages, and user glance
is not available, since this user is added by the package installation
after that.

This fix adds the dependency between packages and the ensure of etc
files.

Change-Id: Ia6523daf69f684c5bdb83255a8e6f6de3160ecc1