gettextize: Don't add config.rpath to EXTRA_DIST
The file is automatically included in the distribution by Automake,
because of an AC_REQUIRE_AUX_FILE invocation. Reported in:
http://savannah.gnu.org/bugs/?48729
* gettext-tools/misc/gettextize.in: Don't add config.rpath to
added_extradist.
