Update the way that privileges are evaluated by the server.  Previously, they were
always based on the authentication identity rather than the authorization identity.  This
means that when the two are different, the result could be incorrect.  One key example of
this is the use of the proxied authorization control by a root user.  In this case, the
proxied authorization would not be subject to access control because the authenticated
user (but not the authorized user) had the bypass-acl privilege.

This change ensures that the proxied-auth privilege is always evaluated as the
authentication identity, but all other priviliges are always evaluated as the
authorization identity.

I have also updated a number of test cases that were incorrectly depending on the
former behavior.

OpenDS Issue Number:  1749