Fix a problem when a target missed a version-update requirement.
This caused build problems, especially in a parallel build
environment.

https://fedorahosted.org/freeipa/ticket/1215

The goal is to not import foreign certificates.

This caused a bunch of tests to fail because we had a hardcoded server
certificate. Instead a developer will need to run make-testcert to
create a server certificate generated by the local CA to test against.

ticket 1134

ticket 1180

ticket 867

https://fedorahosted.org/freeipa/ticket/581

This patch contains 2 parts.

The first part is a small utility to create and validate the current
API. To do this it needs to load ipalib which on a fresh system
introduces a few problems, namely that it relies on a python plugin
to set the default encoding to utf8. For our purposes we can skip that.
It is also important that any optional plugins be loadable so the
API can be examined.

The second part is a version exchange between the client and server.
The version has a major and a minor version. The major verion is
updated whenever existing API changes. The minor version is updated when
new API is added. A request will be rejected if either the major versions
don't match or if the client major version is higher than then server
major version (though by implication new API would return a command not
found if allowed to proceed).

To determine the API version of the server from a client use the ping
command.

ticket 584

This has been completely abandoned since ipa v1 and is not built by default.
Instead of carrying dead weight, let's remove it for now.

Fixes: https://fedorahosted.org/freeipa/ticket/761

Whenever we upgrade IPA such that any data incompatibilities might occur
then we need to bump the DATA_VERSION value so that data will not
replicate to other servers. The idea is that you can do an in-place
upgrade of each IPA server and the different versions own't pollute
each other with bad data.