There are a few changes in this patch set. First we'd like to
support different github/pagure repos being able to be synced
with different instances of JIRA. We currently have two within
Red Hat that we are using, but this strategy should alos support
more than two. Summary of changes in this patch:

• add support for multiple jira instances to the config under the
  config['sync2jira']['jira'] config location. For example if I
  wanted to grab the auth info for the pnt-jira I would access
  config['sync2jira']['jira']['pnt-jira'].
• add support for a 'default_jira_instance' config key that allows
  for a user to specify which jira in the jira dict to use as a default
  in case config entries don't specify a jira instance to use.
• switch function names from functions that that are only called in
  this file to have a preceding underscore (func -> _func)
• make the only functions that get called from outside this file to
  be the ones that crete a client connection to the jira instance
• pass the jira client object around to the private functions