title: Problems with abandoned tmp files in mesh
body: <p>We uploaded some files around 4G to mesh during the development phase. Some uploads might have been aborted. When I had a look at the system's hard drive I saw that the mesh tmp directory consumed a lot of space (around 25G). Some files where about 1 week old.</p>
  
  <p>Is there a way to control the garbage collection for those tmp files?
  Should this be cleaned automatically?</p>
  
  <p>We run mesh 0.24.0 via docker and java-1.8-openjdk
  on Linux srv-cdms 4.9.0-7-amd64 #1 SMP Debian 4.9.110-3+deb9u2 (2018-08-13) x86_64 GNU/Linux</p>