loader-svn: Some SVN origins have occurrences that point to non-existent objects

The following four SVN origins have occurrences that point to revisions that haven't been loaded :

http://ich-sys.googlecode.com/svn/ {'cab5adf110bafe53285ca78f913a860710e83cf5'}
http://project-a.googlecode.com/svn/ {'e89361aaf48051916049a0a14463e0fb78ea8ee6'}
http://shenzipattendesign.googlecode.com/svn/ {'13ae440423bf81c5def18417501839ecd455ce52'}
http://zipeg-gae.googlecode.com/svn/ {'9e3a0cdce5b93b68ad68b7a479d4c8abe889fd5a'}

This needs to be investigated and fixed.

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Migrated from T847 (view on Phabricator)