Slight fix to #15949 to handle emerge queue full (#15960)

Partially restore the existing logic, and try to enqueue a block as before, if the queue is full it will be handled correctly.

src/server/clientiface.cpp

@@ -343,11 +343,7 @@ void RemoteClient::GetNextBlocks (
 			const bool want_emerge = !block || !block->isGenerated();
 
 			// if the block is already in the emerge queue we don't have to check again
-			if (want_emerge && emerge->isBlockInQueue(p)) {
-				nearest_emerged_d = d;
-				continue;
-			}
-
+			if (!want_emerge || !emerge->isBlockInQueue(p)) {
 				/*
 					Check occlusion cache first.
 				 */
@@ -362,6 +358,7 @@ void RemoteClient::GetNextBlocks (
 					m_blocks_occ.insert(p);
 					continue;
 				}
+			}
 
 			/*
 				Add inexistent block to emerge queue.