Remove broken PATH setting

- It didn't work because it looked into /tmp/4/ instead of /tmp/3/
- Fixing that doesn't help, because project/scripts/sbt is not meant to
  be in the PATH: the script will try to run `sbt` to find the real sbt
  launcher, so if it is itself in the PATH we end up with an infinite loop.

Author: smarter

.drone.yml

@@ -40,7 +40,6 @@ pipeline:
     commands:
       - cp -R . /tmp/3/ && cd /tmp/3/
       - git submodule update --init --recursive --jobs 7
-      - export PATH=/tmp/4/project/scripts:$PATH
       - ./project/scripts/sbt community-build/test
 
   test_sbt: