Revert "Reapply /patches/drupal-561990-37-fix-variable_init.patch for variable init stampede"

I'm going to try the site without this for awhile, as this causes the
Duplicate entry 'variable_cache_regenerate' for key 'PRIMARY'
quite a lot. Now we'll probably have the variable stampede...

This reverts commit cb5e1511892112570400285bb1c7992e1f2f97a4.