Set base directory to parent directory within plugin specs
Set base directory to parent directory within plugin specs

This adjustment allows for extensions to be properly discovered after
plugin gem specifications have been activated.

bryson/vagrant,justincampbell/vagrant,chrisroberts/vagrant,bdwyertech/vagrant,marxarelli/vagrant,crashlytics/vagrant,mwrock/vagrant,PatrickLang/vagrant,jtopper/vagrant,marxarelli/vagrant,benh57/vagrant,PatrickLang/vagrant,taliesins/vagrant,bdwyertech/vagrant,marxarelli/vagrant,bryson/vagrant,gitebra/vagrant,mitchellh/vagrant,chrisroberts/vagrant,bdwyertech/vagrant,taliesins/vagrant,crashlytics/vagrant,mitchellh/vagrant,mitchellh/vagrant,benh57/vagrant,mwrock/vagrant,benh57/vagrant,justincampbell/vagrant,sni/vagrant,bshurts/vagrant,mitchellh/vagrant,justincampbell/vagrant,sni/vagrant,bshurts/vagrant,benh57/vagrant,justincampbell/vagrant,taliesins/vagrant,mwrock/vagrant,bdwyertech/vagrant,gitebra/vagrant,chrisroberts/vagrant,PatrickLang/vagrant,crashlytics/vagrant,jtopper/vagrant,sni/vagrant,jtopper/vagrant,jtopper/vagrant,marxarelli/vagrant,taliesins/vagrant,bshurts/vagrant,bryson/vagrant,chrisroberts/vagrant,gitebra/vagrant,mwrock/vagrant,crashlytics/vagrant,sni/vagrant,PatrickLang/vagrant,bryson/vagrant,bshurts/vagrant,gitebra/vagrant