Importd update to survive database restarts.
Patches applied:

 * robert.collins@canonical.com/launchpad--devel--0--patch-130
   merge from rf

 * robert.collins@canonical.com/launchpad--devel--0--patch-131
   merge from rf

 * robert.collins@canonical.com/launchpad--devel--0--patch-132
   update importd to use transactions-when-needed to allow survival of database restarts

 * robert.collins@canonical.com/launchpad--devel--0--patch-133
   pull up sync logic from importd.CVSStrategy to importd.CSCVSStrategy

 * robert.collins@canonical.com/launchpad--devel--0--patch-134
   remove forgotten abort

 * robert.collins@canonical.com/launchpad--devel--0--patch-135
   merge from rf