Attempt to stabilise CouchbaseAutoConfigurationIntegrationTests

Starting the CouchbaseContainer fails intermittently when creation
of the primary index for the bucket fails with a read timeout. The
test doesn't require a primary index for the bucket so this commit
disables it creation in the hope that it will help to stabilise the
test.

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/couchbase/CouchbaseAutoConfigurationIntegrationTests.java

@@ -48,7 +48,7 @@ class CouchbaseAutoConfigurationIntegrationTests {
 	@Container
 	static final CouchbaseContainer couchbase = new CouchbaseContainer().withCredentials("spring", "password")
 			.withStartupAttempts(5).withStartupTimeout(Duration.ofMinutes(10))
-			.withBucket(new BucketDefinition(BUCKET_NAME));
+			.withBucket(new BucketDefinition(BUCKET_NAME).withPrimaryIndex(false));
 
 	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
 			.withConfiguration(AutoConfigurations.of(CouchbaseAutoConfiguration.class))