Remove an exception print from arith/stirling1.c.
Remove an exception print from arith/stirling1.c.

The exception condition "nright < nleft" is equivalent to
"a + b < 2 * floor((a+b)/2)" and hence unnecessary.

fredrik-johansson/flint2,dsroche/flint2,dsroche/flint2,wbhart/flint2,dsroche/flint2,wbhart/flint2,jpflori/flint2,fredrik-johansson/flint2,dsroche/flint2,jpflori/flint2,jpflori/flint2,wbhart/flint2,fredrik-johansson/flint2,jpflori/flint2