Revert pulse sim changes

Author: lcapelluto

tutorials/pulse/7_pulse_simulator_duffing_model.ipynb

@@ -98,16 +98,7 @@
    "cell_type": "code",
    "execution_count": 2,
    "metadata": {},
-   "outputs": [
-    {
-     "name": "stderr",
-     "output_type": "stream",
-     "text": [
-      "/Users/lauren@ibm.com/code/catenv/lib/python3.7/site-packages/qiskit/ignis/characterization/calibrations/pulse_schedules.py:22: DeprecationWarning: the pulse_lib module is deprecated, pulse_lib is renamed to library\n",
-      "  import qiskit.pulse.pulse_lib as pulse_lib\n"
-     ]
-    }
-   ],
+   "outputs": [],
    "source": [
     "import qiskit.pulse as pulse\n",
     "from qiskit.pulse.commands.parametric_pulses import Gaussian, GaussianSquare\n",
@@ -1186,7 +1177,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.3"
+   "version": "3.7.7"
   }
  },
  "nbformat": 4,