labs_vmbuilder: copy all apt configuration
The vmbuilder postinst copy has a manually maintained list of apt
configuration files to copy from /etc/apt/*.d/. Whenever new files are
populated there, we might miss them.
Th copy step is defined in VMBuilder plugins/postinst/__init__.py and is
recursive:
util.run_cmd('cp', '-LpR' ...Replace manually list of files with a list of directories.
Change-Id: I5145d6b33b83bcc14d686233c9e44b1617e22ab5