Removed octave_* shebangfix variables

These are not required and by adding octave SHEBANG_LANG adds these entires and more.

https://www.freebsd.org/doc/en/books/porters-handbook/uses-shebangfix.html

Reported by: matt
Reviewed by: matthew (mentor)
Approved by: matthew (mentor)
Differential Revision: https://reviews.freebsd.org/D11495