plscheme - plscheme: Avoid freeing SPI plan which will already be freed

Log Message:
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Avoid freeing SPI plan which will already be freed at the end of
function transaction. Move plan into a permanent memory context and
let Guile GC do its work. (Patch from Willem Dijkstra & Yeb Havinga.)

Modified Files:
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    plscheme:
        plscheme.c (r1.24 -> r1.25)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/plscheme/plscheme/plscheme.c.diff?r1=1.24&r2=1.25)