Try to prevent #266

We seem to have a bug that we don't find a peer when looking for a peer
in peers.dat . Instead of doing an assertion and crashing the node,
just keep iterating in the loop. The code which computes nId may have an
off-by-one error, such that it looks up an incorrect bucket position and
doesn't find a valid nId.

src/addrman.cpp

@@ -499,7 +499,12 @@ CAddrInfo CAddrMan::Select_(bool newOnly)
                     MilliSleep(kRetrySleepInterval);
             }
             int nId = vvTried[nKBucket][nKBucketPos];
-            assert(mapInfo.count(nId) == 1);
+            // assert(mapInfo.count(nId) == 1);
+            if(mapInfo.count(nId) != 1) {
+                fprintf(stderr,"%s: Could not find tried node with nId=%d=vvTried[%d][%d], mapInfo.count(%d)=%d\n", __func__, nId, nKBucket, nKBuckedPos, nId, mapInfo.count(nId) );
+                continue;
+            }
+
             CAddrInfo& info = mapInfo[nId];
             if (info.IsReachableNetwork()) {
                 //deprioritize unreachable networks
@@ -534,7 +539,12 @@ CAddrInfo CAddrMan::Select_(bool newOnly)
                     MilliSleep(kRetrySleepInterval);
             }
             int nId = vvNew[nUBucket][nUBucketPos];
-            assert(mapInfo.count(nId) == 1);
+
+            if(mapInfo.count(nId) != 1) {
+                fprintf(stderr,"%s: Could not find new node with nId=%d=vvNew[%d][%d], mapInfo.count(%d)=%d\n", __func__, nId, nUBucket, nUBuckedPos, nId, mapInfo.count(nId) );
+                continue;
+            }
+            // assert(mapInfo.count(nId) == 1);
             CAddrInfo& info = mapInfo[nId];
             if (info.IsReachableNetwork()) {
                 //deprioritize unreachable networks