lvextend: fix resizing volumes of different segtype

lvextend: fix resizing volumes of different segtype

When resizing 2 volumes like  thin-pool and it's metadata and they
would be of a different type - command would be actually expecting
both LVs being of a same segtype - and would throw an error in
case they are different.

This patch fixes is by setting a new segtype from last segment of
2nd. extented device.

Also it fixes the possible 'percentage' extension setup that
might have been used for 'primary' volume - while the 'secondary'
LV always goes with direct size - as we do not support 'percentage'
setup for them

This affects maily usage of thin-pool where the extension of
thin-pool data size may also lead to extension of metadata size.