Description of problem:
Installer fails when installing directory server with some missleading errors
when /var is in a FS mounted with noexec option.
It could check if the FS is mounted with noexec or if the file is not
executable and output the right error message and/or possible fix.

Version-Release number of selected component (if applicable):
All versions AFAIK

How reproducible:
Always

Steps to Reproduce:
1.mount -o remount,noexec /var
2.ipa-server-install ...


Actual results:
The installation will fail when setting up the directory server, initially
claiming it can't access the /tmp/file...

Expected results:
The installer will fail with the right error message and/or prompt the user for
applying the solution.

Additional info:
Actually the executable files shouldn't be placed inside /var, they should go
in /usr.