[windows] Use subprocess for safe_exec on windows
[windows] Use subprocess for safe_exec on windows

jtopper/vagrant,signed8bit/vagrant,bshurts/vagrant,benh57/vagrant,chrisroberts/vagrant,signed8bit/vagrant,lukebakken/vagrant,mwrock/vagrant,benh57/vagrant,gitebra/vagrant,bryson/vagrant,bryson/vagrant,PatrickLang/vagrant,sni/vagrant,crashlytics/vagrant,signed8bit/vagrant,jtopper/vagrant,gitebra/vagrant,PatrickLang/vagrant,sni/vagrant,bdwyertech/vagrant,bshurts/vagrant,marxarelli/vagrant,bshurts/vagrant,jtopper/vagrant,lukebakken/vagrant,bshurts/vagrant,crashlytics/vagrant,bdwyertech/vagrant,justincampbell/vagrant,lukebakken/vagrant,mwrock/vagrant,benh57/vagrant,chrisroberts/vagrant,mwrock/vagrant,mitchellh/vagrant,justincampbell/vagrant,crashlytics/vagrant,taliesins/vagrant,bdwyertech/vagrant,gitebra/vagrant,sni/vagrant,taliesins/vagrant,marxarelli/vagrant,justincampbell/vagrant,jtopper/vagrant,signed8bit/vagrant,benh57/vagrant,PatrickLang/vagrant,mitchellh/vagrant,PatrickLang/vagrant,marxarelli/vagrant,mitchellh/vagrant,lukebakken/vagrant,crashlytics/vagrant,mwrock/vagrant,chrisroberts/vagrant,chrisroberts/vagrant,bryson/vagrant,sni/vagrant,bryson/vagrant,justincampbell/vagrant,taliesins/vagrant,mitchellh/vagrant,gitebra/vagrant,taliesins/vagrant,bdwyertech/vagrant,marxarelli/vagrant