Fixing config properties for Zipkin Consumer (#358)

Using the e.g properties from Zipkin Consumer gives the following error when loading the zipkin-server ui:

ERROR: cannot load service names: zipkin/storage/mysql/internal/generated/tables/ZipkinAnnotations
ERROR: cannot load span names: zipkin/storage/mysql/internal/generated/tables/ZipkinSpans

So to fix it you have to explicitly add username and password for the mysql storage.

docs/src/main/asciidoc/spring-cloud-sleuth.adoc

@@ -309,7 +309,7 @@ spring:
     host: ${RABBIT_HOST:localhost}
   datasource:
     schema: classpath:/mysql.sql
-    url: jdbc:mysql://${MYSQL_HOST:localhost}/test
+    url: jdbc:mysql://localhost:3306/zipkin
     username: root
     password: root
 # Switch this on to create the schema on startup:
@@ -319,7 +319,10 @@ spring:
     enabled: false
 zipkin:
   storage:
-    type: mysql
+    type: 
+      mysql:
+        username: root
+        password: root
 ----
 
 NOTE: The `@EnableZipkinStreamServer` is also annotated with
@@ -539,4 +542,4 @@ To disable Zuul support set the `spring.sleuth.zuul.enabled` property to `false`
 You can find the running examples deployed in the https://run.pivotal.io/[Pivotal Web Services]. Check them out in the following links:
 
 - http://docssleuth-zipkin-server.cfapps.io/[Zipkin for apps presented in the samples to the top]
-- http://docsbrewing-zipkin-web.cfapps.io/[Zipkin for Brewery on PWS], its https://github.com/spring-cloud-samples/brewery[Github Code]
+- http://docsbrewing-zipkin-web.cfapps.io/[Zipkin for Brewery on PWS], its https://github.com/spring-cloud-samples/brewery[Github Code]