Handle case where dynamic Jira project properties are modified upstream

[mafrosis]

When issues are created/edited offline, they model the current priorities/issuetypes based on how the Jira project was configured at the last sync.

If these change whilst we have un-sync'd issues locally, then bad things will happen (your local data will be broken).

For example:

1. a project may have Lowest, Low, Medium, High as priorities for the Story issuetype
2. modify a Story-type issue to have priority = Lowest
3. update the project on Jira to have only Low, Medium, High as priorities for the Story issuetype
4. run jiracli push
5. I expect an API error here 😄

[mafrosis]

Closing as not actually a problem. The API will report an invalid priority (or other list value) on push, so that it can be corrected offline