BUG: Missing nil checks on file operations in fetcher

[andrinoff]

Describe the bug
File operations at fetcher/fetcher.go:1029,1035 open files without defer close. If error occurs after open, file descriptor leaks.

To reproduce

1. Open file for attachment processing
2. Error occurs in processing
3. File never closed, descriptor leaked

Expected behavior
Use defer file.Close() immediately after successful open

Matcha version
master

OS
All

Additional context
Files: fetcher/fetcher.go lines 1029, 1035
Missing defer on file.Close()

[Haroka-74]

Hi @andrinoff

This appears to already be fixed in the current code, the file open is wrapped in a closure with defer f.Close() (see #894).

[LeaWhoCodes]

closing