authenticate_twitter doesn't die if auth failed

fixes RT#86270 (reported by yayamamo)
dzil github meta info
github::update
v2.0.2

 [BUG FIXES]
 - authenticate_twitter() was dying if the auth failed.  (RT#86270,
   reported by yayamamo)

 [STATISTICS]
 - code churn: 5 files changed, 71 insertions(+), 4 deletions(-)