Makes v3 API keypairs extension core

Adds os-keypairs to the core list for the V3 API.

Rename os-keypairs to keypairs as part of this change.

Fixes some incorrect urls in test_keypairs which still included
the tenant id

Updates api samples for servers since keypairs is now core and forms
part of the response by default

+DocImpact

Partially implements blueprint nova-v3-api

Change-Id: I8cdf52be0c8b19f7704848029a78373da8018cab
Removed duplicated class in exception.py

This commit 6f9ed562d5f6df1dc16029dcaffd4d2e6601099d had a mistake
which added two same classes ImageDownloadModuleMetaDataError to
exception.py, clear it now.

fixes bug 1223165
Change-Id: I2e7a30a63ab24d1ffb9f33a14db65c6fb3594cb0
Update fedora dev env instructions

I just set up a new dev environment on Fedora.  Update the dev environment docs
to reflect the full list of packages I had to install.

Change-Id: Ifbdea54641094885fee08513f142593befcd465e
Don't return query from db API

The cell_update() method of the sqlalchemy db API returned a Query when
it really intended to return a Cell.  Fix this and tweak the db API test
so that it verifies that the result of this method is a Cell.

Change-Id: I7ab7ea19f00ac2e8c2c73afe8a14f331940b4580
Closes-bug: #1198796
Merge "Makes v3 API keypairs extension core"
Remove out of date list of jenkins jobs

The list of jobs in this doc file was out of date and most of the links
didn't work anymore.  Instead of trying to list out specifics which will
just get out of date again, include a generic pointer to where you can
find results (on code reviews).

Change-Id: Ief65281abae48bee6a679f76068e315227cf6991
Closes-bug: #1199577
Merge "Update fedora dev env instructions"
Merge "Removed duplicated class in exception.py"
Merge "Remove out of date list of jenkins jobs"
Merge "Don't return query from db API"