Fix checkstyle and a test

Author: dadoonet

plugins/discovery-ec2/src/main/java/org/elasticsearch/discovery/ec2/AwsEc2UnicastHostsProvider.java

@@ -174,15 +174,17 @@ && disjoint(securityGroupIds, groups)) {
                             logger.debug("using [{}] as the instance address", address);
                         }
                     }
+                } else {
+                    throw new IllegalArgumentException(hostType + " is unknown for discovery.ec2.host_type");
                 }
                 if (address != null) {
                     try {
                         // we only limit to 1 port per address, makes no sense to ping 100 ports
                         TransportAddress[] addresses = transportService.addressesFromString(address, 1);
                         for (int i = 0; i < addresses.length; i++) {
                             logger.trace("adding {}, address {}, transport_address {}", instance.getInstanceId(), address, addresses[i]);
-                            discoNodes.add(new DiscoveryNode(instance.getInstanceId(), "#cloud-" + instance.getInstanceId() + "-" + i, addresses[i],
-                                    emptyMap(), emptySet(), Version.CURRENT.minimumCompatibilityVersion()));
+                            discoNodes.add(new DiscoveryNode(instance.getInstanceId(), "#cloud-" + instance.getInstanceId() + "-" + i,
+                                addresses[i], emptyMap(), emptySet(), Version.CURRENT.minimumCompatibilityVersion()));
                         }
                     } catch (Exception e) {
                         final String finalAddress = address;

plugins/discovery-ec2/src/test/java/org/elasticsearch/discovery/ec2/Ec2DiscoveryTests.java

@@ -201,7 +201,7 @@ public void testInvalidHostType() throws InterruptedException {
             buildDynamicNodes(nodeSettings, 1);
             fail("Expected IllegalArgumentException");
         } catch (IllegalArgumentException e) {
-            assertThat(e.getMessage(), containsString("No enum constant"));
+            assertThat(e.getMessage(), containsString("does_not_exist is unknown for discovery.ec2.host_type"));
         }
     }