Add build records to avoid redundant rebuilding

[oblitorum]

Close #216

This PR is for avoid rebuilding every modules everytime. It adds build record files ./results/records/{srpms,rpms,sdebs,debs}, records were added one line per package, in format $package_name,$build_artifact_filepath[:$build_artifact_filepath],$package_revision. What it does:

• Before building a package, check the record file, see if current revision is built and build artifacts exist, if not, rebuild this package.
  • When building a ssm-* (forked) package, the revision is the git commit id
  • When building a 3rd-party package, the revision is the %{version} defined in the .spec file.
• After building a package, add/update build record of this package to the record file

Ideally, make clean should not be run and build artifacts should not be removed before the SSM build process, but I seem to see some relevant code in https://github.com/shatteredsilicon/ssm-submodules-builder/blob/master/multibuild#L438-L456, but I'm not 100% sure.

[oblitorum]

Close it since we changed our build process