graphics/tesseract: post-patch command not needed

The sed substitution for %%LOCALBASE%% is no longer needed after a patch file was removed in r506495.

PR: 241654
Submitted by: John Hein <jcfyecrayz@liamekaens.com>
Reviewed by: tcberner (mentor)
Differential Revision: https://reviews.freebsd.org/D22456