_postgis_stats crashes backend on missing stats

[strk]

pg21=# select _postgis_stats('statesp020', 'geom', '2');
The connection to the server was lost. Attempting reset: Failed.
!>                                            

This may be the cause:

pg21=# select st_estimatedextent('public', 'statesp020', 'geom');
ERROR:  stats for "statesp020.geom" do not exist

… and a good output

[strk]

NOTE: _postgis_selectivity isnt' affected, and gives another (better) error message:

pg21=# select _postgis_selectivity('statesp020', 'geom', ST_MakePoint(0, 0), '2');
ERROR:  unable to load statistics! analyze?

[pramsey]

Fixed at r10800