osinstall: Add mising flush_progress call

Signed-off-by: Hector Martin <[email protected]>

Author: marcan

src/osinstall.py

@@ -114,6 +114,7 @@ def download_extras(self):
             data = ucache.read()
             with open(os.path.join(dest, base), "wb") as fd:
                 fd.write(data)
+            self.flush_progress()
 
     def install(self, stub_ins):
         p_progress("Installing OS...")