Handle streams becoming unassociated before the VLOG

It's annoying when the debug printing code crashes...

Change-Id: Ia4140f3ab5d2cecb6a613c56aaf14e85e403431f
Signed-off-by: Austin Schuh <austin.schuh@bluerivertech.com>
diff --git a/aos/network/sctp_lib.cc b/aos/network/sctp_lib.cc
index b522851..babe7ab 100644
--- a/aos/network/sctp_lib.cc
+++ b/aos/network/sctp_lib.cc
@@ -165,8 +165,13 @@
   status.sstat_assoc_id = assoc_id;
 
   socklen_t size = sizeof(status);
-  PCHECK(getsockopt(fd, SOL_SCTP, SCTP_STATUS,
-                    reinterpret_cast<void *>(&status), &size) == 0);
+  const int result = getsockopt(fd, SOL_SCTP, SCTP_STATUS,
+                                reinterpret_cast<void *>(&status), &size);
+  if (result == -1 && errno == EINVAL) {
+    LOG(INFO) << "sctp_status) not associated";
+    return;
+  }
+  PCHECK(result == 0);
 
   LOG(INFO) << "sctp_status) sstat_assoc_id:" << status.sstat_assoc_id
             << " sstat_state:" << status.sstat_state