Fix a data race due dirInfo pointer being read in the main goroutine
by NewMessageStore and written in the anonymous goroutine launched in
Worker.getDirectoryInfo.
To address the issue raised in https://todo.sr.ht/~rjarry/aerc/16, we
use readdir(3) once, parse and cache its results, this replaces
go-maildir library Dir.Flags based stat(3) and filepath.Glob
causing the issue when N (emails) is large.
Signed-off-by: wagner riffel <w@104d.net>
55ae3d2cab