roles/go: remove unsupported parameter "overwrite" for unarchive module

roles/go/tasks/main.yml

@@ -3,7 +3,6 @@
   unarchive: 
   unarchive: 
     src: https://storage.googleapis.com/golang/go1.5.3.linux-amd64.tar.gz 
     src: https://storage.googleapis.com/golang/go1.5.3.linux-amd64.tar.gz 
     dest: /usr/local 
     dest: /usr/local 
-    overwrite: yes
     copy: no
     copy: no
 
 
 - name: make symlinks
 - name: make symlinks