mintUpdate.py: Remove reboot_required flag for a canceled apt

operation.

Fixes #961.

Author: mtwebster

usr/lib/linuxmint/mintUpdate/mintUpdate.py

@@ -2491,6 +2491,7 @@ def on_apt_install_finished(self, transaction=None, exit_state=None):
 
     def on_apt_install_cancelled(self):
         self.logger.write("Install cancelled")
+        self.reboot_required = False
         self.set_status("", "", "mintupdate-updates-available-symbolic", True)
         self.finish_install(False)