fix for Ubuntu 14.04 LTS and Travis

* switches from openoffice.org to libreoffice
* disables 000-default as well as default-ssl using wildcard.
* renames vhost configuration to .conf otherwise a2ensite doesn't see them.
* keeps pip, no downgrading
* fix some path (related to travis)
`VIRTUAL_ENV` may not be defined, and since I'm using `set -o nounset`, things may fail here.  Hence we may need to add something like:

```
VIRTUAL_ENV=${VIRTUAL_ENV:=}
```

in the beginning of the file.

I'll cherry-pick your changes, amend this bit and the below-mentioned message cosmetics, and retest on the vanilla Ubuntu/precise64 vagrant box.