cleanup in base for yum install entries

- introduce install_packages(..., chain=True) to allow chaining on
  onto existing RUN commands
- introduce install_packages(..., clean) which defaults correctly
  but allows you to override if you want to avoid doing extra
  package manager cleanup
- refactored several calls in base to make use of these new features

In general this allows for macros.install_packages to be chained
after other calls

for example

RUN foo && {{ macros.install_packages(..., chain=True) }}

Change-Id: I4b2fe8e13ee3c0fffe77a1179a7af5b534496996

0 files changed, 0 insertions, 0 deletions