[PATCH] Remove useless typedefs

Hi all,
  I have noticed that typedefs.h contains a few typedefs of structs
which do not seem to be defined anywhere, and are not used anywhere.
This patch removes them.

A different case is storeSwapLogData, which is used in
src/test_cache_digest.cc, and whose removal doesn't fail the build
test for some reason. I haven't removed it in the attached patch.

-- 
    /kinkie