[BZ #10871]
* localedata/locales/ru_RU (mon): Rename to...
(alt_mon): This.
(abmon): Rename to...
(ab_alt_mon): This.
(mon): Import from CLDR (genitive case).
(abmon): Copy from the old content except the 5th month which is
now in the genitive case, even when abbreviated.
* localedata/locales/ru_UA: Likewise.
* time/tst-strptime.c (day_tests): Add an actual example of
a difference between %b and %Ob in Russian.