pgsql: Make SPI set SPI_processed for CREATE TABLE AS / SELECT INTO

Log Message:
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Make SPI set SPI_processed for CREATE TABLE AS / SELECT INTO commands;
this in turn causes CREATE TABLE AS in plpgsql to set ROW_COUNT.
This is how it behaved before 7.4; I had unintentionally changed the
behavior in a bit of sloppy micro-optimization.

Modified Files:
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pgsql/src/backend/executor:
spi.c (r1.140 -> r1.141)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/spi.c.diff?r1=1.140&r2=1.141)