pgsql: Rewrite ProcessConfigFile() to avoid misbehavior at EOF, as per

Log Message:
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Rewrite ProcessConfigFile() to avoid misbehavior at EOF, as per report
from Andrus Moor.  The former state-machine-style coding wasn't actually
doing much except obscuring the control flow, and it didn't extend
readily to fix this case, so I just took it out.  Also, add a
YY_FLUSH_BUFFER call to ensure the lexer is reset correctly if the
previous scan failed partway through the file.

Modified Files:
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    pgsql/src/backend/utils/misc:
        guc-file.l (r1.32 -> r1.33)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc-file.l.diff?r1=1.32&r2=1.33)