pgexternaltable - src: erase compile warning

Log Message:
-----------
erase compile warning

Modified Files:
--------------
src/externaltable/exttab:
Interface_FileBuffer.cc (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgexternaltable/src/externaltable/exttab/Interface_FileBuffer.cc?r1=1.4&r2=1.5)
externaltab.c (r1.3 -> r1.4)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgexternaltable/src/externaltable/exttab/externaltab.c?r1=1.3&r2=1.4)
externaltab.h (r1.2 -> r1.3)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgexternaltable/src/externaltable/exttab/externaltab.h?r1=1.2&r2=1.3)