Catch ENOTEMPTY in cleanup_keg
Catch ENOTEMPTY in cleanup_keg

#11904

JCount/brew,MikeMcQuaid/brew,MikeMcQuaid/brew,nandub/brew,nandub/brew,EricFromCanada/brew,Homebrew/brew,Homebrew/brew,EricFromCanada/brew,EricFromCanada/brew,nandub/brew,Homebrew/brew,Homebrew/brew,nandub/brew,MikeMcQuaid/brew,JCount/brew,MikeMcQuaid/brew,JCount/brew,EricFromCanada/brew,JCount/brew