gitk: place file name arguments after options in msgfmt call

gitk: place file name arguments after options in msgfmt call

The build process fails in POSIXLY_CORRECT mode:

  $ gitk@master:1005> POSIXLY_CORRECT=1 make
      * new Tcl/Tk interpreter location
      GEN gitk-wish
  Generating catalog po/zh_cn.msg
  msgfmt --statistics --tcl po/zh_cn.po -l zh_cn -d po/
  msgfmt: --tcl requires a "-l locale" specification
  Try 'msgfmt --help' for more information.
  make: *** [Makefile:76: po/zh_cn.msg] Error 1

The reason is that option arguments cannot occur after the first
non-option argument. Move the file name last.

Reported-by: Nathan Royce <nroycea+kernel@gmail.com>
Signed-off-by: Johannes Sixt <j6t@kdbg.org>