pgsql: Persuade GIN to react to control-C in a reasonable amount of time

Log Message:
-----------
Persuade GIN to react to control-C in a reasonable amount of time
while building a GIN index.

Modified Files:
--------------
pgsql/src/backend/access/gin:
gininsert.c (r1.12 -> r1.13)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/gin/gininsert.c?r1=1.12&r2=1.13)