* New upstream snapshot. - tests: Add CiTestCase common parent for all curtin tests. - vmtests: Remove force flag for centos curthooks - tools/jenkins-runner: improve tgtd cleanup logic - tests: Drop EOL Wily Vivid and Yakkety tests. - Disable yum plugins when installing packages, update ca-certs for https - Rename centos_network_curthooks -> centos_apply_network_config. - tests: in centos_defaults use write_files for grub serial. - write_files: write files after extract, change write_files signature. - pass network configuration through to target for ubuntu and centos - tests: disable yakkety tests. - tools/launch: automatically pass on proxy settings to curtin - Add top level 'proxy' to config, deprecate top level http_proxy. - tools/curtainer: fix to enable deb-src for -proposed. - Use unshare to put chroot commands in own pid namespace.