More fixes after the recent import from CLDR-31

After the recent import of month names from CLDR (bug 21217) more
imports are also needed, mostly abbreviated month names.

	* localedata/locales/br_FR (abmon): Reworded "Eve " to "Mezh".

	* localedata/locales/fy_NL (abmon): Reworded "Maa" (March) to
	"Mrt" and "Maa" (May) to "Mai".

	* localedata/locales/lg_UG (abmon): Reworded "Jun" to "Juu".

	* localedata/locales/ln_CD (abmon): "yan", "fbl", "msi",
	and so on.

	* localedata/locales/mn_MN (abmon): "1-р сар", "2-р сар",
	"3-р сар", and so on.

	* localedata/locales/vi_VN (abmon): Reworded "Th01" to "Thg 1",
	"Th02" to "Thg 2" and so on.

	* localedata/locales/yo_NG (abday): "Àìkú", "Ajé", "Ìsẹ́gun",
	and so on, also comment updated to match the new content.
	(day): "Ọjọ́ Àìkú", "Ọjọ́ Ajé", "Ọjọ́ Ìsẹ́gun", and so on.
	(abmon): "Ṣẹ́rẹ́", "Èrèlè", "Ẹrẹ̀nà", and so on.
	(mon): Comment updated to match the actual content.
	(d_t_fmt): Changed "%A" to "%a" and "%B" to "%b".

	* localedata/locales/zu_ZA (abmon): "Jan", "Feb", "Mas",
	and so on, also comment updated to match the new content.
	(mon): comment updated to match the actual content.