This ebuild is for a newer version of trac than is currently in portage. It also adds the ~amd64 keyword, which appears to work fine with my limited testing (as it should, since the app itself is pure python).
Created attachment 35786 [details] ebuild for trac 0.7.1
The 0.7-postinst-en.txt also needs to be copied to 0.7.1-postinst-en.txt, but since the file needs no modification I did not post it as an attachment.
*** This bug has been marked as a duplicate of 52929 ***