ggsave() can't be used with devices taking file as argument instead of filename

[bwiernik]

In ggsave(), if device is specified and the device takes the file argument instead of filename, ggsave fails with an error: unused argument (filename = filename)

library(ggplot)
p <- qplot(cars[[1]], cars[[2]])
ggsave("plot.pdf", p, device = pdf)

For the grDevices devices that take file, ggsave customizes the call to use file instead, but this doesn't work for devices from other packages, such as devEMF::emf or Cairo::CairoSVG.

This appears to be caused by these changes to remove partial argument matching.
#2355
#2364

It would be nice if ggsave automatically caught this error, then retried with file instead of filename.