Remove general assumption in get_packages()

get_packages() always included 'general' as a default 'service' file.
Remove this assumption and add it explicitly to the primary package
installation call.  This allows get_package() to be used in other places
where 'general' is not desired to be included.

Change-Id: I1eed4386d073d6ae9534aedae32654208c6662e8
Add stack phases to extras.d handling

Add hooks to stack.sh, unstack.sh and clean.sh to call the extras.d
scripts at multiple points in stack.sh.  This allows these scripts to
perform installation and startup tasks at similar times as they would
if integrated into stack.sh.

extras.d/70-tempest.sh is present as an example of the structure
of these scripts.

See extras.d/README.md for more information.

Change-Id: Ic1fe522559b94d204d6c0319a2e3d23684c8d028
Fix fixup_stuff.sh package permissions fix

There are a number of different attempts to fix this issue, specifcally on RHEL6.
None of them actually get it right.
* This does not upgrade an OS installed package because we trust them to not make
  these sorts of permissions mistakes. Also we do not have nor want to figure out the
  right version that the OpenStack projects will require.
* This specfically targets the upstream package versions as we do not know how
  later versions behave.

This should address the following reviews:
* https://review.openstack.org/#/c/50540/
* https://review.openstack.org/#/c/51233/ (1238707)
* https://review.openstack.org/#/c/51651/ (1239747)
* https://review.openstack.org/#/c/51843/
* https://review.openstack.org/#/c/51838/
* https://review.openstack.org/#/c/52148/ (1236941)

Change-Id: I99906451dc25654628187b383e8893cce0e276bf
Merge "Remove general assumption in get_packages()"
Merge "Fix fixup_stuff.sh package permissions fix"
Merge "Add stack phases to extras.d handling"