gerrit changes depending one on another

[Maarten Bosmans]

I just tried to push 3 changes to gerrit with a topic set.
The core/logerrit script does not have an option to set a topic, so I
did a manual git push.

This did not work:
`git push origin HEAD:refs/for/master -o topic=tdf53698`
It failed with the message "fatal: the receiving end does not support
push options"

The other (deprecated?) way did work:
`git push origin HEAD:refs/for/master/topic=tdf53698`
But, I see now that here I should have left out 'topic='.

May be the best way would be to add an -o (or --topic) option to
`logerrit submit`. This should use the master/topic refname at first
and when push options are supported on LO gerrit switch to that.

Maarten