当我使用此命令启动 apache 时sudo /usr/sbin/httpd -k start，出现以下错误：
Syntax error on line 18 of /etc/httpd/conf.d/ssl.conf:
SSLPassPhraseDialog: file '/usr/libexec/httpd-ssl-pass-dialog' does not exist
我看到该/etc/httpd/conf.d/ssl.conf文件正在请求访问此文件：
# Pass Phrase Dialog:
# Configure the pass phrase gathering process.
# The filtering dialog program (`builtin' is a internal
# terminal dialog) has to provide the pass phrase on stdout.
SSLPassPhraseDialog exec:/usr/libexec/httpd-ssl-pass-dialog
但我不知道这个文件应该从哪里获取，该文件是否应该与 apache 或 mod_ssl 一起安装？