REL-367 Update csd nexus deploy

Not only simpler, but it now also works, which is always a good thing.

In addition to these changes, users will require a settings file in $HOME/.ant/settings.xml (can't use our usual ~/.m2/settings.xml, which will be read if ~/.ant/settings.xml is not present.)  The new settings.xml just needs to contain:
```
<settings>
  <servers>
    <server>
      <id>nexus</id>
      <username>???</username>
      <password>???</password>
    </server>
  </servers>
</settings>
```
...with appropriate values for `username` and `password`.

After that, building and deploying to nexus is just a matter of:
```
ant maven-build
ant maven-publish -Dmvn.publish.repo=csd
```