doc: Translate German documentation left-overs

Translate a bit of out-of-place German documentation in the middle of
the English documentation, for consistency.

Signed-off-by: Magnus Olsson <mago@hms.se>
installer: Run preinst scripts before scanning MTD

Since MTD scanning (and UBI volume when CONFIG_UBIVOL) occurs before the
preinst scripts run, any new UBI volumes created by the scripts will not
be detected. This will likely result in "volume not found" errors during
the UBI image install phase, if it tries to write to a newly created volume
(even though it does exist).

This patch swaps the order of MTD scanning and preinst scripts so that MTD
scanning is postponed until all preinst scripts have completed. This is mostly
useful for CONFIG_UBIVOL users.

Signed-off-by: Magnus Olsson <mago@hms.se>