heptapod-ci: simpler CI

We have a mercurial clone available in the docker image now. This will same some
time to avoid a full Mercurial clone for each run.
5 jobs for topic/stable/heptapod-ci in 4 minutes and 21 seconds (queued for 1 second)
Name Stage Failure
failed
tests-py2-cext Test
adding file changes
added 4977 changesets with 11584 changes to 471 files (+10 heads)
new changesets bbeef801409c:816119be10ca
updating to branch default
297 files updated, 0 files merged, 0 files removed, 0 files unresolved
just before HgSha
Checking out Hg node edc29a909339e6dfe1197b4a06d4e56a12085615 as topic/stable/heptapod-ci... (skip)
abort: unknown revision 'edc29a909339e6dfe1197b4a06d4e56a12085615'!
ERROR: Job failed: exit code 1
failed
flake8 Test
adding file changes
added 4977 changesets with 11584 changes to 471 files (+10 heads)
new changesets bbeef801409c:816119be10ca
updating to branch default
297 files updated, 0 files merged, 0 files removed, 0 files unresolved
just before HgSha
Checking out Hg node edc29a909339e6dfe1197b4a06d4e56a12085615 as topic/stable/heptapod-ci... (skip)
abort: unknown revision 'edc29a909339e6dfe1197b4a06d4e56a12085615'!
ERROR: Job failed: exit code 1