VWR-22162 FIXED 'I can't add negative signs to TWIST in Edit Mode'

Probably a regression from the prevalidator rework - was enforcing non-negative int when precision=0 (i.e. non-float), should have been enforcing only full int range.

indra/llui/llspinctrl.cpp

@@ -128,7 +128,7 @@ LLSpinCtrl::LLSpinCtrl(const LLSpinCtrl::Params& p)
 	}
 	else //should accept int numbers
 	{
-		params.prevalidate_callback(&LLTextValidate::validateNonNegativeS32);
+		params.prevalidate_callback(&LLTextValidate::validateInt);
 	}
 	
 	params.follows.flags(FOLLOWS_LEFT | FOLLOWS_BOTTOM);