[Evolution] String change, made plural forms of two strings

[Milan Crha <mcrha redhat com>]

        Hello,
I just committed a fix for bug [761993], where have been requested to
make some UI strings plural forms (the strings are long, I'd rather not
copy them here). It was done with commit [2]. Translator comments had
been added as well.
        Bye,
        Milan

[761993] https://bugzilla.gnome.org/show_bug.cgi?id=761993
[2] https://git.gnome.org/browse/evolution/commit/?id=21316bd