Fixed issues introduced by recent 'portal changes' commit.

src/main/java/net/minecraft/server/EntityBoat.java

@@ -383,6 +383,7 @@ public class EntityBoat extends Entity {
             }
 
             if (this.passenger != null && this.passenger.dead) {
+                this.passenger.vehicle = null;
                 this.passenger = null;
             }
         }

src/main/java/net/minecraft/server/EntityMinecart.java

@@ -583,6 +583,7 @@ public class EntityMinecart extends Entity implements IInventory {
             }
 
             if (this.passenger != null && this.passenger.dead) {
+                this.passenger.vehicle = null;
                 this.passenger = null;
             }
 

src/main/java/net/minecraft/server/ServerConfigurationManager.java

@@ -231,6 +231,8 @@ public class ServerConfigurationManager {
             cserver.getPluginManager().callEvent(respawnEvent);
             location = respawnEvent.getRespawnLocation();
             entityplayer.health = 20;
+            entityplayer.fireTicks = 0;
+            entityplayer.fallDistance = 0;
         } else {
             location.setWorld(this.server.a(i).getWorld());
         }