Delete argsize to fix a -Wunused-but-set-variable warning with gcc 4.9

[ngie]

Summary

Delete argsize to fix a -Wunused-but-set-variable warning with gcc 4.9

The variable isn't actually checked -- just the end result which gets returned
from the function

MFC after: 1 month
Sponsored by: EMC / Isilon Storage Division

[araujo]

Not sure about this change, because if asprintf() can't allocate sufficient memory it will return -1. Maybe a (void)asprintf(.....) could be better. I guess that int is there to silent the -1 return.

[delphij]

I've no idea what I was thinking about :-/ but your change is good.

[ngie]

In D5156#109662, @araujo wrote:

Not sure about this change, because if asprintf() can't allocate sufficient memory it will return -1. Maybe a (void)asprintf(.....) could be better. I guess that int is there to silent the -1 return.

I'll add (void) for clarity -- thanks for the feedback :).