DLASQ3, SLASQ3: stop modifying QMAX

[jschueller]

QMAX was documented as [in] but was written inside the qd-array reversal block. The caller recomputes QMAX immediately after the call, so the update has no useful effect. Remove it to match the documented intent

Closes #326

[langou]

Thanks @jschueller.

I agree with Issue #326.

That being said, I do not think this PR is the good fix.

A better fix could be to change QMAX from [in] in DLASQ3 to [in/out].

I disagree with the statement: "The caller recomputes QMAX immediately after the call, so the update has no useful effect." (0) It is correct that QMAX gets recomputed whenever a split is found but this is not all the time. (1) QMAX is used in DLASQ3 as in/out and we keep on building up the value as we go, (2) also, it is used in in the IF statement Z( 4*N0 ).LE.TOL2*QMAX in DLASQ2.

All in all, I think this is PR needs to be changed to QMAX being flagged as [in/out] in DLASQ3. I agree that this would fix Issue #326.

[jschueller]

ok, done