buf_file/buf_file_single: fix to ignore placeholder based path. fix #2582

[repeatedly]

Signed-off-by: Masahiro Nakagawa repeatedly@gmail.com

Which issue(s) this PR fixes:
Fixes #2582

What this PR does / why we need it:
fluentd uses { and } for placeholders and these characters are special in Dir.glob.
Should be escaped before call Dir.glob.

Docs Changes:
No need.

Release Note:
Same as title.

[ganmacs]

This patch looks good. but can we change child elements(in this context buffer section) not to access the parent node's setting(in this context match section and @type is file). #2582 (comment)

I don't think path in buffer section and path in match section are completely different.

[repeatedly]

can we change child elements(in this context buffer section) not to access the parent node's setting(in this context match section and @type is file)

Which point? out_file set path to buffer's path when <buffer> doesn't have path. buf_file doesn't access out_file's path.

[ganmacs]

You're right. I misread… out_file sets path to buffer's path here