gettext: fix for low-version recipe

Make gettext-native in 0.16.1 recipe provides virtual/gettext-native like
what gettext-native in 0.19.6 recipe does. Otherwise we would fail to start
to do a world build if gettext and gettext-native are set to the low version.
Error message is like below.

  ERROR: Multiple versions of gettext-native are due to be built

(From OE-Core rev: a0bdbd8f38d8d2ca0687f4353b715087f946247a)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/gettext/gettext_0.16.1.bb

@@ -9,7 +9,7 @@ PR = "r6"
 DEPENDS = "virtual/libiconv"
 DEPENDS_class-native = ""
 PROVIDES = "virtual/libintl virtual/gettext"
-PROVIDES_class-native = ""
+PROVIDES_class-native = "virtual/gettext-native"
 
 SRC_URI = "${GNU_MIRROR}/gettext/gettext-${PV}.tar.gz \
            file://gettext-vpath.patch \