sos/sendMail job should create queued failed mail file with failed.sos. instead of ending with "~" sign

Current situation

When using the class package sos.net.SOSMail to send an email (as e.g. the job soss.scheduler.managed.JobSchedulerManagedMailJob is doing}} and the email fails (e.g. wrong port) it creates sos.2019-09-24.133305.306.email~ in the configured mail directory .

How to reproduce

• Create a sample sos.scheduler.managed.JobSchedulerManagedMailJob to send an email. 
• Then change the SMTP mail host in the factory.ini
• restart the JobScheduler master
• Then start the mail job from JOC-Cockpit
• Then you can find files in the mail directory ./jobscheduler/jobscheduler_id/mail with "~" sign

  sos.2019-09-24.133305.306.email~

Desired Behavior

Instead of creating the file sos...email~ the file failed.sos.....email should be created. If so the job sos.scheduler.job.JobSchedulerDequeueMailJob can handle this file and try to resend it

Patch available

• To patch 1.12.10: https://download.sos-berlin.com/patches/patch_for_JITL-574_mail_failed_queue_on_version_1.12.10.zip
• To patch 1.13.0: https://download.sos-berlin.com/patches/patch_for_JITL-574_mail_failed_queue_on_version_1.13.0.zip