Detection and filetype setting are done in ftdetect scripts
filetype is set to subtype.epuppet so ftplugin and syntax file loading
is done by (n)vim owns scripts (ftplugin.vim and syntax/synload.vim)

Added more test to detect if g:epuppet_default_subtype is defined in
.vimrc

If using
```
  'for': ['puppet', 'epuppet']
```
vim-plug load ftdetect/puppet.vim, that set filetype to 'subtype.epuppet'
then as this does not strictly match 'epuppet' vim-plug remove
vim-puppet from &rtp and syntax and ftplugin file could not be loaded.
The solution is to add a wildcard
```
  'for': ['puppet', '*epuppet']
```