Close the key only if we have opened it (it's not the case when the subkey name is...
drwxr-xr-x - cis
drwxr-xr-x - irc
drwxr-xr-x - msvc6
drwxr-xr-x - os2
drwxr-xr-x - posix
drwxr-xr-x - reactos
drwxr-xr-x - rosapps
drwxr-xr-x - rosky
drwxr-xr-x - vms