Refactor from deprecated getAliasedStringArray

Update ServletComponentScanRegistrar to make use of Spring Framework's
updated alias support with ASM reading.

See gh-6337

spring-boot/src/main/java/org/springframework/boot/web/servlet/ServletComponentScanRegistrar.java

@@ -76,8 +76,7 @@ class ServletComponentScanRegistrar implements ImportBeanDefinitionRegistrar {
 	private Set<String> getPackagesToScan(AnnotationMetadata metadata) {
 		AnnotationAttributes attributes = AnnotationAttributes.fromMap(
 				metadata.getAnnotationAttributes(ServletComponentScan.class.getName()));
-		String[] basePackages = attributes.getAliasedStringArray("basePackages",
-				ServletComponentScan.class, metadata.getClassName());
+		String[] basePackages = attributes.getStringArray("basePackages");
 		Class<?>[] basePackageClasses = attributes.getClassArray("basePackageClasses");
 		Set<String> packagesToScan = new LinkedHashSet<String>();
 		packagesToScan.addAll(Arrays.asList(basePackages));