ask about loading conf-file on goto

after 70c6b2d, close-ycmd and then reverting and then M-. would show the
'load conf.py?' question in the warnings buffer
s/handle-notify-exception/handle-extra-conf-exception/
Merge pull request #102 from unhammer/handle-goto-exception

ask about loading conf-file on goto
Merge pull request #105 from abingham/handle-goto-exception

Handle goto exception