Code simplification.
Code simplification.

* subversion/libsvn_ra_serf/commit.c
  (derive_old_val): Remove a level of indirection, type casts and memory
    allocations. Add an output flag instead. Add a doc string.
  (proppatch_walker): Update accordingly.

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