use newer adobe_connect gem

fixes CNVS-6734

also displays errors encountered when joining
a conference rather than leaving it unhandled

testing steps:
* a legacy conference should work to start or join
  after the update
  * prior performing the update, create a conference
    that is not yet started
  * prior performing the update, create a conference
    that has started but not yet ended
  * verify both conferences can be started or joined

* new conferences should work to create and join

* conference unique ID clashes should error gracefully
  * create a new conference, in a console, change the
    setting :meeting_url_id to be set to an existing
    meetings meeting_url_id and verify attempts to join
    it fail with a nicer error message.

  * in the console:
    c = WebConference.find [insert ID of meeting]
    c.settings[:meeting_url_id] = 'canvas-meeting-[ID of legacy meeting]'
    c.save
  * reload the conferences web page and attempt to join
    the meeting

Change-Id: I39085eba54f1cfe51335d3df5c81df1930791a8e
Reviewed-on: https://gerrit.instructure.com/22196
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jon Willesen <jonw@instructure.com>
QA-Review: Cam Theriault <cam@instructure.com>
Product-Review: Mark Ericksen <marke@instructure.com>

Gemfile

@@ -22,7 +22,7 @@ gem 'barby',          '0.5.0'
 gem 'bcrypt-ruby',    '3.0.1'
 gem 'builder',        '2.1.2'
 if !CANVAS_RAILS3
-  gem 'canvas_connect', '0.1.0'
+  gem 'canvas_connect', '0.1.1'
 end
 gem 'daemons',        '1.1.0'
 gem 'diff-lcs',       '1.1.3',  :require => 'diff/lcs'

app/controllers/conferences_controller.rb

@@ -142,6 +142,9 @@ class ConferencesController < ApplicationController
         redirect_to named_context_url(@context, :context_url)
       end
     end
+  rescue StandardError => e
+    flash[:error] = t(:general_error_with_message, "There was an error joining the conference. Message: '%{message}'", :message => e.message)
+    redirect_to named_context_url(@context, :context_conferences_url)
   end
 
   def close