Close the ConfigManager at end of command

Fixes issue #1.
3 jobs for master in 1 minute and 43 seconds
Status Job ID Name Coverage
  Build Src
passed #5703
build:src

00:00:17

 
  Build Pkg
passed #5704
build:pkg

00:01:04

 
  Upload
passed #5705
upload:pkg

00:00:21