Fix intermittent error in exercises/floating_ips.sh

Every once in a while I see this error running floating_ips.sh:

/devstack/exercises/floating_ips.sh:184:ping_check
/devstack/functions:356:_ping_check_neutron
/devstack/lib/neutron:904:die
[ERROR] /devstack/lib/neutron:904 [Fail] Could ping server

I think the problem is that it immediately tries to ping right
after the icmp rule is deleted.  Add a timeout and check so we
at least wait one second.

Change-Id: I753ec257fa12f6d2ddff1a5b1909e32d8995e173
Add heat_stack_owner role for heat trusts usage

Heat supports deferred operations via keystone trusts,
and we'd like to make that the default.  To do this, we
require a new role, which is the default role specified
in heat.conf trusts_delegated_roles, heat_stack_owner.

Add the role to the admin/demo users so they can create
heat stacks when we make deferred_auth_method=trusts the
default.

Change-Id: Idfc70ee89428c23f5965e643486ff2ad9566471c
Related-Bug: #1286157
Don't install vim or locate by default

Devstack doesn't need vim or locate, if someone wants to use them, they
can just install them afterwards.

Change-Id: I00f27c20c86d89465e4aefc67ed645a309c09a03
Merge "Don't install vim or locate by default"
Merge "Fix intermittent error in exercises/floating_ips.sh"
Merge "Add heat_stack_owner role for heat trusts usage"