clean trash on every command
clean trash on every command

Summary: currently we only move dirs to trash and clean trash on version bump. change this to clean that trash on every command.

Reviewed By: styurin

fbshipit-source-id: 157867d5dd

shs96c/buck,nguyentruongtho/buck,SeleniumHQ/buck,zpao/buck,rmaz/buck,zpao/buck,romanoid/buck,JoelMarcey/buck,rmaz/buck,zpao/buck,SeleniumHQ/buck,rmaz/buck,shs96c/buck,Addepar/buck,rmaz/buck,nguyentruongtho/buck,shs96c/buck,romanoid/buck,romanoid/buck,rmaz/buck,rmaz/buck,Addepar/buck,Addepar/buck,shs96c/buck,SeleniumHQ/buck,Addepar/buck,rmaz/buck,romanoid/buck,brettwooldridge/buck,JoelMarcey/buck,shs96c/buck,romanoid/buck,nguyentruongtho/buck,shs96c/buck,brettwooldridge/buck,zpao/buck,JoelMarcey/buck,romanoid/buck,shs96c/buck,JoelMarcey/buck,kageiit/buck,SeleniumHQ/buck,rmaz/buck,romanoid/buck,facebook/buck,JoelMarcey/buck,brettwooldridge/buck,romanoid/buck,JoelMarcey/buck,Addepar/buck,shs96c/buck,shs96c/buck,JoelMarcey/buck,brettwooldridge/buck,SeleniumHQ/buck,shs96c/buck,nguyentruongtho/buck,brettwooldridge/buck,rmaz/buck,shs96c/buck,rmaz/buck,kageiit/buck,Addepar/buck,rmaz/buck,JoelMarcey/buck,facebook/buck,kageiit/buck,JoelMarcey/buck,romanoid/buck,romanoid/buck,romanoid/buck,SeleniumHQ/buck,brettwooldridge/buck,brettwooldridge/buck,facebook/buck,zpao/buck,JoelMarcey/buck,nguyentruongtho/buck,brettwooldridge/buck,brettwooldridge/buck,SeleniumHQ/buck,facebook/buck,kageiit/buck,facebook/buck,brettwooldridge/buck,brettwooldridge/buck,facebook/buck,shs96c/buck,Addepar/buck,zpao/buck,shs96c/buck,SeleniumHQ/buck,SeleniumHQ/buck,kageiit/buck,facebook/buck,Addepar/buck,SeleniumHQ/buck,SeleniumHQ/buck,JoelMarcey/buck,kageiit/buck,Addepar/buck,SeleniumHQ/buck,brettwooldridge/buck,kageiit/buck,Addepar/buck,Addepar/buck,SeleniumHQ/buck,Addepar/buck,rmaz/buck,JoelMarcey/buck,Addepar/buck,romanoid/buck,brettwooldridge/buck,zpao/buck,nguyentruongtho/buck,JoelMarcey/buck,romanoid/buck,nguyentruongtho/buck,rmaz/buck