pgsql: Swap the order of testing for control characters and for column

Log Message:
-----------
Swap the order of testing for control characters and for column delimiter in
CopyAttributeOutText(), so that control characters are converted to the
C-style escape sequences even if they happen to be equal to the column
delimiter (as is true by default for tab, for example).  Oversight in my
previous patch to restore pre-8.3 behavior of COPY OUT escaping.  Per report
from Tomas Szepe.

Modified Files:
--------------
    pgsql/src/backend/commands:
        copy.c (r1.290 -> r1.291)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/copy.c?r1=1.290&r2=1.291)