lvcreate: raid0 needs default number of stripes

lvcreate: raid0 needs default number of stripes

Commit 3928c96a37941d765bf467d82502cd2aec7fd809 introduced
new defaults for raid number of stripes, which may cause
backwards compatibility issues with customer scripts.

Adding configurable option 'raid_stripe_all_devices' defaulting
to '0' (i.e. off = new behaviour) to select the old behaviour
of using all PVs in the VG or those provided on the command line.

In case any scripts rely on the old behaviour, just set
'raid_strip_all_devices = 1'.

- resolves rhbz1354650