Emit updateTimeout() when regular position updates aren't received.

The documentation indicates that the updateTimeout() signal should be
emitted once when the source determines that regular updates will no
longer be received.

[ChangeLog][QtPositioning][Geoclue] The Geoclue position source now
emits the updateTimeout() signal when position updates do not arrive in
a timely manner.

Change-Id: I87c31a60a8e718a0ab72a1e270a93e967307f77a
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
Send requested update interval to Geoclue providers.

Send the requested update interval to the active Geoclue provider. The
update interval is sent by passing and 'UpdateInterval' option to the
provider. Not all Geoclue providers support this setting, in which case
they will report position changes at their default rate.

The Geoclue position info source no longer limits the rate of position
updates internally.

[ChangeLog][QtPositioning][Geoclue] The Geoclue position info source
provider no longer internally filters position updates to the
requested update interval.

Change-Id: I96a112575173d4fa485905b1885a98fe43da1153
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>