This reverts commit 911d13f4.

This has consequences I didn't realize until Pete Biggs talked about them
in evolution-list mailing list.

It's for newly configured accounts only, and it's done only due to
recent change on the Yahoo! POP3 servers, as discussed for example
here: https://bugzilla.gnome.org/show_bug.cgi?id=778562

Store/use local data version only when the pagination in libgdata is
used, otherwise the auto-update of the internal data won't work.

There had been a check whether folder content changed, but the current
values were not properly saved and also the UNSEEN response from the SELECT
command was used like being a number of unseen messages, but it's
a sequence number of the first unseen message instead.

There was no credentials prompt when using Google authentication (OAuth2),
only an error about secret not found had been shown. This fixes it and
lets the user to enter Google credentials when not found in the keyring.

Reported downstream as:
https://bugzilla.redhat.com/show_bug.cgi?id=1418915

The reason is that the other places which require complete message also
ignore any errors and the error was not respected anyway, thus it could
result in a spread of errors on the console. This way one can search
when being offline and the result will be for the available messages.

The upcoming libical release can have the deprecated symbol removed
and the replacement is available in the requested minimum version
of the libical already, thus no dependency change by replacing it.