Handle "dynamic auto" ports differently on the Catalyst

Don't align them with either trunk or access ports here. They're not
the same as either, and if we've imported a switch with some of these
then it will cause headaches later. That's also quite common, as it's
the default port mode on the C3750.

Instead, return "dynamic" and let higher-up code deal with it.

Change-Id: Ib8d7435016c3cf15b83c0caa80c5699c0fc13d5e
diff --git a/drivers/CiscoCatalyst.py b/drivers/CiscoCatalyst.py
index 8112f41..7bd5774 100644
--- a/drivers/CiscoCatalyst.py
+++ b/drivers/CiscoCatalyst.py
@@ -524,8 +524,13 @@
                     mode = match.group(1)
                     if mode == 'static access':
                         return 'access'
-                    if mode == 'trunk' or mode == 'dynamic auto':
+                    if mode == 'trunk':
                         return 'trunk'
+                    # Needs special handling - it's the default port
+                    # mode on these switches, and it doesn't
+                    # interoperate with some other vendors. Sigh.
+                    if mode == 'dynamic auto':
+                        return 'dynamic'
             return mode
 
         except PExpectError: