[PATCH] exit codes for the action_* methods

This patch adds exit codes to the action_* methods.
All the methods will return 0, except the svnmerge avail action when no
candidates are found. It will then return 2

This can be used when creating an automated merge (svn-automerge)

We use this to allow developers to set a property on their
developerbranch and a cronjob on the server will run svnmerge every hour
on all the branches that have this property set.
That way we keep the branches in sync with their source.

To speed up the whole cronjob we needed a way to detect wether a branch
needs an svnmerge. So we added exit codes and return 2 if the
action_avail finds no revs to merge.

Code based on a patch from Digium
http://svnview.digium.com/svn/repotools/svnmerge?r1=5&r2=6

-- 
Michiel van Baak
michiel_at_vanbaak.eu
http://michiel.vanbaak.eu
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"Why is it drug addicts and computer aficionados are both called users?"