Redmine

Issue:
If a locally unhandled exception is raised when receiving a mail, the error is not logged.

How to repro:
1. Add the line

raise "An error occurred" 

as the first line of the receive method
2. Run the rake task

rake redmine:email:receive_imap RAILS_ENV="production" host=imap.gmail.com port=993 move_on_success=Success move_on_failure=Failure username=***** password=*****

on a mailbox which has at least one unread mail in the mailbox
3. Check the redmine log
Result:
D, [2018-05-24T17:25:53.647960 #16786] DEBUG -- : Receiving message 21674
D, [2018-05-24T17:25:53.648109 #16786] DEBUG -- : Message 21674 can not be processed

Expected result:
D, [2018-05-24T17:25:53.647960 #16786] DEBUG -- : Receiving message 21674
E, [2018-05-24T17:25:53.648076 #16786] ERROR -- : MailHandler: an unexpected error occurred when receiving email: An error has occured
D, [2018-05-24T17:25:53.648109 #16786] DEBUG -- : Message 21674 can not be processed

Suggested fix: define logger as self.logger instead as just logger in the MailHandler class