Revert "Add Clam plugin"

This reverts commit 19afe152b40c53680169972434b7068d6bbf0da8.

I never use it.
Update paths in Ansible setup files
Simplify configuration of temporary files

Revert 1072cfd325bbc6869ad54b2c5228c4af720d5a74 and update
f9205bfa61077ff1581e2acc9030dd38f1678a26 in order to have a simple
configuration.

In short:

- Don't use different cache directories for Linux and OS X.
- Put swap, backup and undo files in the same directory
  (backup is disabled, but set its location anyway for completeness).
- Prefer ~/.cache/vim//, otherwise fall back to Vim's defaults.
- The double // indicates to use the complete path to name the files.