Description of problem:
Similarly to bug #1362762, placeholder is removed, but now in case that author exists in INI file but it is empty (see below).

After discussion, the much better will be new concept of *building* of modules,
without any modifications in script files during building. Instead of including
some lines into check scripts, P-A itself should handle this before run
of the script; with same result as lines are included in scripts
(sorry for rugged sentence, hope the idea is clear).

In that way, probably we could ignore the "author" key completely.

Version-Release number of selected component (if applicable):
preupgrade-assistant-2.1.10


Steps to Reproduce:
Set author of a module to empty string. INI file could seems like this:
[preupgrade]
content_title       = foo title
content_description = foo description
author       =          
solution     = solution.txt
check_script = check.sh 


Actual results:
Placebolder in check script is removed and module doesn't work.


Expected results:
Module will not be broken after *build* by preupgr-xccdf-compose.