patch: fix the json_pack format specifier in patch_build
patch: fix the json_pack format specifier in patch_build

Fixes a bug introduced in b67116db44f006ae1763ae9e1c7a172f4e3c2457 where the final '/' isn't written in the patch stack. This caused a bug in the logs, and could break some other place assuming a / here.

thpatch/thcrap,thpatch/thcrap,thpatch/thcrap,thpatch/thcrap,thpatch/thcrap