mkman: fix g_options.tex generation

* INSTALLED_OPTIONS_PROGRAM_NAME contains full path due to find
* INSTALLED_OPTIONS_PROGRAM_NAME will generate INSTALLED_OPTIONS_PROGRAM_NAME.tex
* compare only the basename ${ ##*/} of the files

Change-Id: I4b590f7794f49424a37297bf72fcd2aeb9475d25
Merge "mkman: fix g_options.tex generation" into release-4-6