Make cf_plplot.in be correctly sourced when running configure in the tmp directory.
Make cf_plplot.in be correctly sourced when running configure in the
tmp directory.

svn path=/trunk/; revision=2530

FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot