pgexternaltable - src: fix a bug about memory leak when config bad file

Log Message:
-----------
fix a bug about memory leak when config bad file option

Modified Files:
--------------
    src/externaltable:
        externaltab.c (r1.2 -> r1.3)

(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgexternaltable/src/externaltable/externaltab.c.diff?r1=1.2&r2=1.3)
        externaltab.h (r1.1 -> r1.2)

(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgexternaltable/src/externaltable/externaltab.h.diff?r1=1.1&r2=1.2)

Added Files:
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    src/externaltable:
        buffer.cc (r1.1)

(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgexternaltable/src/externaltable/buffer.cc?rev=1.1&content-type=text/x-cvsweb-markup)
        buffer.h (r1.1)

(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgexternaltable/src/externaltable/buffer.h?rev=1.1&content-type=text/x-cvsweb-markup)
        streambuffer.cc (r1.1)

(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgexternaltable/src/externaltable/streambuffer.cc?rev=1.1&content-type=text/x-cvsweb-markup)
        streambuffer.h (r1.1)

(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgexternaltable/src/externaltable/streambuffer.h?rev=1.1&content-type=text/x-cvsweb-markup)