isl_aff_insert_dims: drop unused local variable
isl_aff_insert_dims: drop unused local variable

Additionally, plug in the assigned value where it could have been used.

Reported-by: Michael Kruse <e37bdc670d6573b8890bd5bd5b982b09bd5220e8@meinersbur.de>
Signed-off-by: Sven Verdoolaege <235c10dd23b819f81cdc9756a251746bc184cab6@gmail.com>

Meinersbur/isl,Meinersbur/isl,Meinersbur/isl,Meinersbur/isl