Also add controller circuit id to all relevant circpad loglines. This will
make debugging any future issues like #30992 much easier.

Delete src/or/buffers.c which was fixup'ed in 0.2.9 but moved in 0.3.5.
The 0.2.9 fix is not required for the 0.3.5 patch.
Resolves merge conflict caused by 30041.