[PATCH] Increase the maximum value track_activity_query_size

Hi Hackers,

Some ORMs may generate queries larger than the maximum possible value of 
track_activity_query_size (100 kB).
Is there any reasons to limit the maximum value of 
track_activity_query_size to such small value?
Increasing the maximum value to 1 MB will help partially solve this 
problem.
Also in the file postgresql.conf.sample pointed maximum value 
track_activity_query_size (before that it was not specified).

--
Vyacheslav Makarov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company