Wait for IDLE stop had been related to time out set on the connection,
which could be very long (as set by IDLE call itself). The server
could be also unreachable due to network change, but this might
not be always caught by the output stream. Having up to 10 seconds
wait will make sure the IDLE stop request will not wait for too long.

This change is to workaround issue when Google server doesn't accept time format
being passed to it with libgdata in queries, which can result in badRequest/invalid
GData errors. Simply re-run the query without the time constraint.

Without the setlocale() call the translated strings were not localized.

When sendmail is not available when building, the corresponding SENDMAIL_PATH
variable contains useless value. This change makes it possible to define
SENDMAIL_PATH as an environment variable, which then points to
the sendmail binary (like "/usr/sbin/sendmail"), and if not set, then
it is searched for and when even that fails, then a default is used.

There had been also SYSTEM_MAIL_DIR variable, but it was not used
anywhere, thus it's removed now.

The issue with missing sendmail had been reported at:
https://bugzilla.redhat.com/show_bug.cgi?id=1468890