General issue for useless, vague, or non-existent error logging

This is catchall issue to document all instances of bad error logging.

1. gitlab-runner 3304: Include additional error details when upload fails
2. gitlab-ce 46344: Include more context in pipeline error logging
3. omnibus-gitlab 2630: Docker image does not contain sendmail
4. gitlab-ee 5864: Pipeline showing error: yaml invalid: undefined error when git fsck reports problems with associated Git repository