Buildbot: mips_4kec packages architecture has failed since 23 days

[Hannu Nyman]

mips_4kec packages architecture has consecutively failed at the packages 
builtbot since 23 days. (Last ok build on 30 July)

The failure looks strange, almost like the architecture dir would have been 
deleted from the buildbot farm.
Failure happens after the actual packages build, in the feeds.conf generation 
step:

https://buildbot.openwrt.org/main/packages/#/builders/38/builds/293/steps/25/logs/stdio

./scripts/feeds list -s -f > bin/packages/mips_4kec/feeds.conf
  in dir /builder/mips_4kec/build/sdk (timeout 1200 secs)
  watching logfiles {}
  argv: b'./scripts/feeds list -s -f > bin/packages/mips_4kec/feeds.conf'
  environment:
   HOME=/builder
   HOSTNAME=009499ad9abd
   LANG=en_US.utf8
PATH=/opt/venv/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
   PWD=/builder/mips_4kec/build/sdk
   SHLVL=1
  using PTY: False
/bin/sh: 1: cannot create bin/packages/mips_4kec/feeds.conf: Directory 
nonexistent
program finished with exit code 2
elapsedTime=0.011390


similar error at the signpack step:

find bin/packages/mips_4kec/ -mindepth 1 -maxdepth 2 -type f -name sha256sums 
-print0 -or -name Packages -print0 -or -name packages.adb -print0 | xargs -0 
tar -czf sign.tar.gz
...
find: ‘bin/packages/mips_4kec/’: No such file or directory
tar: Cowardly refusing to create an empty archive