Fix up ctest for the case of plabort (which does not set an exit code), but which does have an error message including the string "PLPLOT ERROR" which is now looked for.
Fix up ctest for the case of plabort (which does not set an exit code), but
which does have an error message including the string "PLPLOT ERROR" which
is now looked for.

svn path=/trunk/; revision=7816

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