Remove the keystone group and user since its created
when the keystone package is installed and the image is built.
Tested by checking that the keystone user/group was still
on the image after they were removed from base-passwd.
Story: 2009221
Task: 43417
Signed-off-by: Charles Short <charles.short@windriver.com>
Change-Id: I404d8d17cfc901c4cb2fed3b79a05c440c063641