osd: EC optimizations bug in OSDMap::clean_temps

osd: EC optimizations bug in OSDMap::clean_temps

OSDMap clean_temps clears pg_temp for a PG when the up set
matches the acting_set. For optimized EC pools the pg_temp
is reordered to place primary shards first, this function
was not calling pgtemp_undo_primaryfirst to revert the
reordering.

This meant that a 2+1 EC PG with up set [1,2,3] and
a desired acting set [1,3,2] re-ordered the acting
set to produce pg_temp as [1,2,3] and then deleted this
because it equals the up set.

Calling pgtemp_undo_primaryfirst makes this code work
as intended.

Signed-off-by: Bill Scales <bill_scales@uk.ibm.com>