Use communicate() in get_rev_list()

This should allow get_rev_list() to work for submodules
merge master -D org: PR 157 (Milestone command)
merge master -D org: PR 158 (Fix scc check-prs by using find_branching_point())
merge master -D org

Repository: openmicroscopy/snoopycrimecop
Already up-to-date.

Merged PRs:
  # PR 157 sbesson 'Milestone command'
  # PR 158 sbesson 'Fix scc check-prs by using find_branching_point()'

Generated by SCC-merge#290 (http://ci.openmicroscopy.org/job/SCC-merge/290/)