Retry job creation if initial attempts fail

Currently we don't actually verify the job we attempted to create actually gets
created. This commit updates this to attempt the job creation up to 3 times and
fail if it does not succeed. This way we can be more sure the job has been
created and will function successfully.

Signed-off-by: Moses Mendoza <moses@puppetlabs.com>
Merge pull request #165 from MosesMendoza/maint/master/retry_job_creation

Retry job creation if initial attempts fail