Unable to install 7.2.7 on CentOS Linux release 7.3 (version 7.1.5 works fine)

No actually I pasted the entire content of that file.
Checked once again to confirm.
This is it!

Here's the Apache log file contents:

[ 2018-11-19 02:35:11.8891 10080/7fed42ca8700 age/Cor/SecurityUpdateChecker.h:466 ]: A security update is available for your version (5.1.2) of Passenger, we strongly recommend upgrading to version 5.3.5.

[ 2018-11-19 02:35:11.8892 10080/7fed42ca8700 age/Cor/SecurityUpdateChecker.h:471 ]: Additional information:
Several critical security issues have been fixed since v5.1.2, due to an issue in Passenger < 5.1.6 we can not display more info.

[ 2018-11-19 15:35:12.5808 10080/7fed42ca8700 age/Cor/SecurityUpdateChecker.h:466 ]: A security update is available for your version (5.1.2) of Passenger, we strongly recommend upgrading to version 5.3.5.

[ 2018-11-19 15:35:12.5808 10080/7fed42ca8700 age/Cor/SecurityUpdateChecker.h:471 ]: Additional information:
Several critical security issues have been fixed since v5.1.2, due to an issue in Passenger < 5.1.6 we can not display more info.

[Mon Nov 19 21:29:07.976750 2018] [autoindex:error] [pid 10117] [client 10.0.3.1:42582] AH01276: Cannot serve directory /var/www/html/: No matching DirectoryIndex (index.html,index.php) found, and server-generated directory index forbidden by Options directive

Just to clarify, we have a virtual machine that runs only ProjeQtOr, and nothing else.
And this is the log for that machine for that day.
So my engineer thinks that this "Passenger" must be a part of ProjeQtOr -- Can't be anything else...

I have asked our engineer to follow your tips and revert.

But then a question arises as to why this same system worked fine with all the earlier versions of ProjeQtOr?
Nothing was changed.
Has the new version changed in some respect?