plg_install_location and ihs_install_location not used in httpd.conf

[umeli]

Setting the variable plg_install_location is not used in the ihs installer role. Lots of hard coded stuff inside the httpd.conf.j2 template: /opt/IBM/HTTPServer instead of something like {{ __ihs_install_location }}

[sabrina-yee]

Thanks for the feedback, internal issue ticket created to investigate.