tcp_debug: don't abort when socket can't be removed

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: I8daa317fed8fc7e720dccb70fd5f7fc74fde423f

osmopy/obscvty.py

@@ -74,7 +74,10 @@ class VTYInteract(object):
             return
 
         if debug_tcp_sockets:
-            VTYInteract.all_sockets.remove(self.socket)
+            try:
+                VTYInteract.all_sockets.remove(self.socket)
+            except ValueError:
+                pass
             print "Socket: closing %s:%d %r (%d sockets open)" % (
                     self.host, self.port, self.socket,
                     len(VTYInteract.all_sockets))