Dependency determination and ctags issues

Ran into two issues attempting to install vim from source on a `hashicorp/precise64` Ubuntu box.

1. Dependencies attribute was not being determined correctly in the attributes file.

```
==> default: [2014-06-25T10:15:56+00:00] FATAL: Chef::Exceptions::Package: package[python-devel] (vim::source line 24) had an error: Chef::Exceptions::Package: No version specified, and no candidate version available for python-devel`
```

2. Installing ctags.

```
==> default: [2014-06-25T10:21:15+00:00] FATAL: Chef::Exceptions::Package: package[ctags] (vim::source line 30) had an error: Chef::Exceptions::Package: ctags is a virtual package provided by 2 packages, you must explicitly select one to install
```