Fix logic of the float16 check.

theano/scalar/basic.py

@@ -3301,7 +3301,8 @@ class Composite(ScalarOp):
                     ["%%(o%i)s" % i for i in xrange(len(self.fgraph.outputs))]))
 
         for var in self.fgraph.variables:
-            if var.owner is None and var not in self.fgraph.inputs:
+            if var.owner is None:
+                if var not in self.fgraph.inputs:
                     # This is an orphan
                     if isinstance(var, Constant):
                         subd[var] = var.type.c_literal(var.data)