In git diff headers, make the paths shown after "a/" and "b/" always reflect the left and right side of the diff, respectively.
In git diff headers, make the paths shown after "a/" and "b/" always
reflect the left and right side of the diff, respectively.

Before this change, a 2-URL diff between ^/trunk and ^/branch would show
paths like "a/branch/foo.c b/branch/foo.c". Now, the paths shown reflect
the nature of the diff more accurately: "a/trunk/foo.c b/branch/foo.c".

Sometimes both paths are equal, sometimes they aren't. But that really
depends on the global diff operation, not on the individual changes the
git diff headers are printing. Yet a few of the git header printing functions
were only receiving one path.

* subversion/libsvn_client/diff.c
  (print_git_diff_header_added, print_git_diff_header_deleted,
   print_git_diff_header_copied, print_git_diff_header_added,
   print_git_diff_header_modified): Expect two paths, and print the first one
    after "a/" and the second one after "b/". Also, swap argument order of
    the _copied() function from (path, copyfrom_path) to the more natural-
    looking order (copyfrom_path, path).
  (print_git_diff_header_moved): Rename to ...
  (print_git_diff_header_renamed): ... this, because the header also says
   "rename to/from". Also, same kind of change as above, including the
   path/copyfrom_path swap.
  (print_git_diff_header): Adjust caller.

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