CBLT-82:  ./${PKGR} ${PREFIX} ${PREFIXP} ${REVISION} ${GITSPEC} ${PLATFORM}

Change-Id: I9bcfaa4a4611d0854028652b90eeceb34238a27c
CBLT-82:  don't forget to export RPM_ROOT_DIR

This is needed by rpmbuild, called by package-rpm.rb
By default rpms get built in home directory.
Must set ~/.rpmmacros to:

  %_topdir    %(echo $RPM_ROOT_DIR)

  %_rpmdir     %_topdir/RPMS
  %_srcrpmdir  %_topdir/SRPMS
  %_sourcedir  %_topdir/SOURCES

Change-Id: I5af163f530e3e239ba5d1a255fd3f0a35e1e97fb