[Rd] incorrect linetype with pdf device (PR#14128)

[baptiste auguie]

Dear all,

Running this minimal example,

library(grid)
postscript("test-123456.eps")
grid.newpage()
grid.lines(gp=gpar(lty="123456", lineend = "butt"))
dev.off()

produces eps output with the following setdash description towards the
end of the file,

## [ 0.00 3.00 2.00 5.00 4.00 7.00] 0 setdash

I consulted the postscript reference manual (page 667 *), which
indicates that the array should rather be [1 2 3 4 5 6] as intended
(and as produced by, e.g., quartz())

(*): http://www.adobe.com/products/postscript/pdfs/PLRM.pdf

Regards,

baptiste