internal/build: revert raising the chunk size for PPA

internal/build/util.go

@@ -130,7 +130,7 @@ func render(tpl *template.Template, outputFile string, outputPerm os.FileMode, x
 // The destination host may be specified either as [user@]host[: or as a URI in
 // the form sftp://[user@]host[:port].
 func UploadSFTP(identityFile, host, dir string, files []string) error {
-	sftp := exec.Command("sftp", "-B", "262144")
+	sftp := exec.Command("sftp")
 	sftp.Stderr = os.Stderr
 	if identityFile != "" {
 		sftp.Args = append(sftp.Args, "-i", identityFile)