Reverted function in delta_logp to not accept mode argument

Author: fonnesbeck

pymc3/step_methods/metropolis.py

@@ -433,6 +433,6 @@ def delta_logp(logp, vars, shared):
 
     logp1 = pm.CallableTensor(logp0)(inarray1)
 
-    f = theano.function([inarray1, inarray0], logp1 - logp0, mode=self.mode)
+    f = theano.function([inarray1, inarray0], logp1 - logp0)
     f.trust_input = True
     return f