wget: Remove -t from calls

The wget from busybox we are using ignores the -t option,
although it does not throw errors in the currently used version.

However, specifying the -t option in calls where it is not used
is misleading, so it should be removed.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Reviewed-by: Christian Dresel <fff@chrisi01.de>
Reviewed-by: Robert Langhammer <rlanghammer@web.de>