This patch forwards the DISTRO_APT_PREMIRRORS environment variable into the container when using the kas-container script. This variable is commonly used to externally set mirrors for debian apt, e.g. in a CI environment. Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>