Fixes a bug that deletes the staging directory before deployment when specifying ".*" in :copy_exclude

When using the following config:

    set :deploy_via, :copy
    set :copy_exclude, [".*"]

The temp directory used for staging a copy is itself deleted ("."), so the deploy fails.  This commit sanitizes the ".*" by removing "." and ".." from the list of deleted folders.  Using ".*" is helpful in excludes since it allows you to exclude all locally hidden files using that syntax.  This also brings the exclusion syntax inline with the .gitignore syntax.