On the 'move-tracking-2' branch: Tweak error message formatting.

* subversion/svnmover/svnmover.c
  (branch_merge_subtree_r,
   sub_main): Start error messages with a capital letter and don't end
    them with a newline.

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/move-tracking-2@1636595 13f79535-47bb-0310-9956-ffa450edef68