Bad log level for jira.issue_create

[lnlrbr]

Log level for creating a simple issue should be info and not warning (https://github.com/atlassian-api/atlassian-python-api/blob/master/atlassian/jira.py#L1616)

[gonchik]

Hi @lnlrbr ,
thanks, will adjust later

[gkowalc]

I added a PR @gonchik - I reviewed all the logging levels across all the products (one left - bitbucket) and I downgraded logging levels where it made sense - I left a few log.warn when it is actually required.