print -dashed fails with gnuplot backend

[Jarno Rajahalme]

I used to get the different dashed lines with gnuplot, but with the current tip 
I get an error instead (gnuplot 4.4.2, was the same with 4.4.0):

octave:1> plot([10 5; 2 16; 3 7], '-')
octave:2> legend('a', 'b')
octave:3> print test.eps -dashed -deps
error: set: invalid handle (= -16.0668)
error: called from:
error:   [...]octave/scripts/plot/print.m at line 377, column 9
octave:3> 

Playing with it, sometimes it works, but even then the dashes are all the same 
simple ones.

Any ideas?

  Jarno