gluon-config-mode-geo-location: add "Altitude" string to the POT file

package/gluon-config-mode-geo-location/i18n/gluon-config-mode-geo-location.pot

@@ -13,6 +13,9 @@ msgstr ""
 msgid "Longitude"
 msgstr ""
 
+msgid "Altitude"
+msgstr ""
+
 msgid "Show node on the map"
 msgstr ""