cosmetic: early exit instead of if-cascade

It appears that during some error conditions, the socket will not be in the tcp
socket debug tracking list, and on top of an exception this barfs as well.
Let's not care about the tcp debug list and avoid confusing error messages.

Change-Id: Ib7b0e45fa1f5551da2fc81b71dcc227eee533f44

osmopy/obscvty.py

@@ -70,14 +70,16 @@ class VTYInteract(object):
 
     def _close_socket(self):
         global debug_tcp_sockets
-        if self.socket:
-            if debug_tcp_sockets:
-                VTYInteract.all_sockets.remove(self.socket)
-                print "Socket: closing %s:%d %r (%d sockets open)" % (
-                        self.host, self.port, self.socket,
-                        len(VTYInteract.all_sockets))
-            self.socket.close()
-            self.socket = None
+        if self.socket is None:
+            return
+
+        if debug_tcp_sockets:
+            VTYInteract.all_sockets.remove(self.socket)
+            print "Socket: closing %s:%d %r (%d sockets open)" % (
+                    self.host, self.port, self.socket,
+                    len(VTYInteract.all_sockets))
+        self.socket.close()
+        self.socket = None
 
     def _is_end(self, text, ends):
         """