Update CachedGraphTransaction.java

1. fix the bug when vertex updated, but the edge cache associated with that vertex was not updated. Here we simply clear all edge cache when  any vertex changes.

hugegraph-core/src/main/java/com/baidu/hugegraph/backend/cache/CachedGraphTransaction.java

@@ -394,8 +394,11 @@ protected final void commitMutation2Backend(BackendMutation... mutations) {
                 }
             }
 
-            // Update edge cache if any edges change
-            if (edgesInTxSize > 0 && this.enableCacheEdge()) {
+            // Update edge cache if any vertex or edge change
+            // for vertex change, the edge associated with that vertex should also be updated
+            // here we just clear all the edge cache , before we use a more precise strategy
+            boolean invalidEdgesCache = (this.edgesInTxSize() + updates.size() + deletions.size()) > 0;
+            if (invalidEdgesCache) {
                 // TODO: Use a more precise strategy to update the edge cache
                 this.edgesCache.clear();
                 this.notifyChanges(Cache.ACTION_CLEARED, HugeType.EDGE, null);