Fix log and test for NeutronAPI.update_port_dhcp_opts

The unit tets for NeutronAPI.update_port_dhcp_opts were raising the
wrong exception, and would pass regardless of the behaviour of
update_port_dhcp_opts.

This patch causes the mock to raise a neutron_client exception and
correctly asserts that ironic.common.neutron.NeutronAPI converts the
neutron client expcetion to an ironic exception.

It also adjusts the LOG behavior of this method to properly record
the exception traceback, which could be useful in determining the
failure in the neutron client.

Change-Id: I6f231b6a823386709b5778d140d6aa48ae4997ce
Fix broken doc links on the index page

Commit 017f99120b1 did not move documentation from dev/ to developer/.
The links on the index page were updated incorrectly.
This change reverts that and fixes the broken links.

Change-Id: Ia2f3703589c469bfc2a5204bdd3becc4b09efd0d
Return correct HTTP response codes for create ops

When creating {chassis,node,port} resources the incorrect HTTP
response code was being returned. (was 200, now returning 201).

Closes-Bug: #1272596

Change-Id: Ic0fb2cc1794841dcef7009990f0ae482d71b1242
Merge "Fix broken doc links on the index page"
Merge "Fix log and test for NeutronAPI.update_port_dhcp_opts"