fetch + plugin id mapping logic is out of order

When attempting to install a plugin from local filesystem or a github url, if the plugin id listed in plugin.xml contains a . can be mapped to an npm module, then npm is used.

repro:

cordova plugin add https://github.com/EddyVerbruggen/Insomnia-PhoneGap-Plugin

or if you have a clone:

cordova plugin add /MyRepos/Insomniac/