Stop sending an InterceptResponse to a PolicyCheckRequest for log_subcmds.

There's no real reason for the command to wait for sudo send back a
response that will always be a PolicyAcceptMessage.

src/exec_intercept.h

@@ -20,6 +20,7 @@
 #define SUDO_EXEC_INTERCEPT_H
 
 enum intercept_state {
+    INVALID_STATE,
     RECV_HELLO_INITIAL,
     RECV_HELLO,
     RECV_SECRET,