Revert "Catch KeyError if constraint name is missing"

Author: isikhar

diffcalc/hkl/you/constraints.py

@@ -423,9 +423,4 @@ def set_constraint(self, name, value):  # @ReservedAssignment
         return "%s : %s --> %s" % (name, old_str, new_str)
 
     def get_constraint(self, name):
-        try:
-            value = self.all[name]
-        except KeyError:
-            return None
-        return None if value is None else value * TODEG
-    
+        value = self.all[name]