Fix a few more integer size warnings.
Fix a few more integer size warnings.

* subversion/libsvn_delta/xdelta.c
  (blocks): Update member to apr_size_t.
  (add_block, compute_delta): Update param to apr_size_t.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion