[patch/rfc] Don't complain about unknown OSABI

[Andrew Cagney]

> Hello,
> 
> The attached patch removes the warning message that is printed when the OSABI is unknown (all the sniffers failed).
> 
> When debugging an embedded executable, there is no OSABI info.  Hence I don't think the warning should be issued.  This can be seen when debugging a GCC created, mips-elf executable.
> 
> thoughts?

All positive, I've checked it in.

Andrew