Escape globs in directory names when using copy_cache

The queue_files method of the copy deploy strategy passes directory
names to Dir.glob. This commit causes glob characters in the path to
be escaped beforehand. Otherwise, directories with names like 'app{1}'
would fail to be matched.
Merge pull request #316 from bison/copy_strategy_escape_globs

Escape globs in directory names when using copy_cache