Remove obsolete *page[_marker] methods from LDAP backend.

Change-Id: I87a75c9f1cd3f6cb3f233df6e54125f35ae4631c
keystone : Use Ec2Signer utility class from keystoneclient

The Ec2Signer class has been moved to python-keystoneclient,
so we can remove the internal implementation and import the
keystoneclient version

blueprint ec2signer-to-keystoneclient

Change-Id: I19d8575ab8b972467ce280a6197ae762da1ce790
bug 1134802: fix inconsistent format for expires_at and issued_at

Notice we have to use fraction of second precision to prevent PKI token ID
overlap.

Change-Id: Icfc192c08ab5b4db02547ef6f077fa7f32210835
Trusts

Blueprint trusts

creates a trust.  Using a trust, one user (the trustee), can then
create tokens with a subset of another user's (the trustor) roles and
projects.
If the impersonate flag in the trust is set, the token user_id is set
to the trustor's user ID
If the impersonate flag is not set, the token's user_is is set to the
trustee's user ID

check that both trustor and trustee are enabled prior to creating
the trust token.

sql and kvs backends
sql upgrade scripts
unit tests for backends, auth and v3 api
modifications to the trust controller for creating tokens
Authenticates that only user can be trustor in create
Deleting a trust invalidates all tokens created from that trust
Adds the trust id and the id of the trustee to the header of the token
policy rules for trust

This version has a workaround for testing against the KVS version
of the Service catalog

Change-Id: I5745f4d9a4180b59671a143a55ed87019e98ec76
Expand v3 trust test coverage

Change-Id: Ie697e19c2fa0e4ac203ff24aa9efa23c25ea6ccd
Merge "Remove obsolete *page[_marker] methods from LDAP backend."
Merge "bug 1134802: fix inconsistent format for expires_at and issued_at"
Merge "Trusts"
Merge "Expand v3 trust test coverage"
Merge "keystone : Use Ec2Signer utility class from keystoneclient"