Login to JIRA before doing any other work

Change-Id: Id83b9cefdc3073581ec8b090432686449d2e9bd9
Support JIRA Kerberos auth in checkbugs

Change-Id: I2838c224f5aaae04c7b475de7f8b0d92c5332e5b
Make Gerrit consistency check optional

Change-Id: I02cbf3cb9f9a4c4b5c1228d619987f0d045d95e7