Fix segfault when shutting down before fully loading

TheBlueMatt · TheBlueMatt · commit c0025d0a92e4 · 2017-07-27T15:03:05.000-04:00
This was introduced by 3192975. It can be triggered easily when canceling DB upgrade from pre-per-utxo.
diff --git a/src/init.cpp b/src/init.cpp
@@ -216,7 +216,9 @@ void Shutdown()
     }
 
     // FlushStateToDisk generates a SetBestChain callback, which we should avoid missing
-    FlushStateToDisk();
+    if (pcoinsTip != nullptr) {
+        FlushStateToDisk();
+    }
 
     // After there are no more peers/RPC left to give us new data which may generate
     // CValidationInterface callbacks, flush them...

Original file line number	Diff line number	Diff line change
`@@ -216,7 +216,9 @@ void Shutdown()`
`216`	`216`	`}`
`217`	`217`
`218`	`218`	`// FlushStateToDisk generates a SetBestChain callback, which we should avoid missing`
`219`		`- FlushStateToDisk();`
	`219`	`+ if (pcoinsTip != nullptr) {`
	`220`	`+ FlushStateToDisk();`
	`221`	`+ }`
`220`	`222`
`221`	`223`	`// After there are no more peers/RPC left to give us new data which may generate`
`222`	`224`	`// CValidationInterface callbacks, flush them...`