Ignore plugin mapper when a git spec is specified

We had a project with this in the config.xml:

<plugin name="net.yoik.cordova.plugins.screenorientation" spec="https://github.com/Telerik-Verified-Plugins/ScreenOrientation.git" />

However, the cordova plugin mapper has an entry for net.yoik.cordova.plugins.screenorientation that was telling it to fetch from npm.

The cordova prepare output said it was being fetched from npm, but there was a folder in ./plugins/ with the old ID and then it said that it failed to install for iOS because it was already installed for Android, and also said that it was fetching from npm again.

The best solution is probably to avoid going through the plugin mapper if a spec is a git reference (or maybe if there's a spec at all?)