pgsql: Make plancache store cursor options so it can pass them to

Log Message:
-----------
Make plancache store cursor options so it can pass them to planner during
a replan. I had originally thought this was not necessary, but the new
SPI facilities create a path whereby queries planned with non-default
options can get into the cache, so it is necessary.

Modified Files:
--------------
pgsql/src/backend/commands:
prepare.c (r1.72 -> r1.73)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/prepare.c.diff?r1=1.72&r2=1.73)
pgsql/src/backend/executor:
spi.c (r1.177 -> r1.178)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/spi.c.diff?r1=1.177&r2=1.178)
pgsql/src/backend/tcop:
postgres.c (r1.531 -> r1.532)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/tcop/postgres.c.diff?r1=1.531&r2=1.532)
pgsql/src/backend/utils/cache:
plancache.c (r1.7 -> r1.8)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/cache/plancache.c.diff?r1=1.7&r2=1.8)
pgsql/src/include/commands:
prepare.h (r1.26 -> r1.27)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/commands/prepare.h.diff?r1=1.26&r2=1.27)
pgsql/src/include/utils:
plancache.h (r1.5 -> r1.6)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/plancache.h.diff?r1=1.5&r2=1.6)