sg: remove an unused variable
sg: remove an unused variable

The 'data_dir' variable is not used in sg_common_write(), hence
remove this variable.

Signed-off-by: Bart Van Assche <28563a2d387a4f8f033bf7abbf80937064dfbe0c@sandisk.com>
Acked-by: Douglas Gilbert <54dff2264884c355ed5584a3b7f1530b4b26921e@interlog.com>
Signed-off-by: Christoph Hellwig <923f7720577207a44b32e59bbfbea59d27f1ae8e@lst.de>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs