pgsql: Remove extraneous backslash from 'fixseq.sql' example --- mea

Log Message:
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Remove extraneous backslash from 'fixseq.sql' example --- mea culpa
certainly. Per report from George Woodring.

Modified Files:
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pgsql/doc/src/sgml:
release.sgml (r1.417 -> r1.418)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/release.sgml.diff?r1=1.417&r2=1.418)