fix wrong import of gamma

Author: Frédéric Chapoton

src/sage/rings/asymptotic/asymptotics_multivariate_generating_functions.py

@@ -1785,7 +1785,8 @@ def asymptotics_smooth(self, p, alpha, N, asy_var, coordinate=None,
         """
         from sage.calculus.functions import jacobian
         from sage.calculus.var import function
-        from sage.functions.other import factorial, gamma, sqrt
+        from sage.functions.other import factorial, sqrt
+        from sage.functions.gamma import gamma
         from sage.functions.log import exp, log
         from sage.matrix.constructor import matrix
         from sage.modules.free_module_element import vector