Changed url rewrite sample regex to be more specific

Author: mikaelm12

samples/RewriteSample/UrlRewrite.xml

@@ -1,7 +1,7 @@
 <rewrite>
   <rules>
     <rule name="Rewrite 20 to 10" stopProcessing="true">
-      <match url="(.*)" />
+      <match url="^app$" />
       <conditions>
         <add input="{QUERY_STRING}" pattern="id=20" />
       </conditions>