Split up the main 'svn merge' function, simply hoisting a chunk of code out
into a separate function.  This is in preparation for fixing issue #4316
"Merge errors out after resolving conflicts".

* subversion/svn/merge-cmd.c
  (run_merge): New function ...
  (svn_cl__merge): ... extracted from here.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1446286 13f79535-47bb-0310-9956-ffa450edef68
* subversion/tests/cmdline/diff_tests.py
  (local_tree_replace): Following up on r1446279, update expected result.
    (or commit file missing from original commit)


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1446288 13f79535-47bb-0310-9956-ffa450edef68