dpkg-deb: Fix cleanup for control member with restricted directories

It was discovered that dpkg-deb does not properly sanitize directory permissions when extracting a control member into a temporary directory, which is

documented as being a safe operation even on untrusted data. This may result in leaving temporary files behind on cleanup. Given automated and repeated execution of dpkg-deb commands on

adversarial .deb packages or with well compressible files, placed

inside a directory with permissions not allowing removal by a non-root

user, this can end up in a DoS scenario due to causing disk quota

exhaustion or disk full conditions.