bug#28873: 26.0.60; error while restoring frameset

[martin rudalics]

> Not sure if the following will shed some light:
>
> (gdb) xbacktrace
> "modify-frame-parameters" (0xbfaea0)
> "let*" (0xbfb100)
> "frameset--restore-frame" (0xbfb290)

I checked in a fix.  Please try again.

Thanks, martin