Change GT.M install location to /opt/lsb-gtm/$gtm_ver_$gtm_arch

According to LANANA: http://www.lanana.org/lsbreg/packages/packages.txt
GT.M's directory name should be lsb-gtm.

Move to using /opt/ as the base directory since this pacakage is
manually installed and easier to find in /opt rather than /usr/lib.