AMBARI-8233. Blueprint fails when %HOSTGROUP::name% followed by another % (alejandro)

ambari-server/src/main/java/org/apache/ambari/server/controller/internal/BlueprintConfigurationProcessor.java

@@ -79,7 +79,7 @@ public class BlueprintConfigurationProcessor {
   /**
    * Compiled regex for hostgroup token.
    */
-  private static Pattern HOSTGROUP_REGEX = Pattern.compile("%HOSTGROUP::(\\S+)%");
+  private static Pattern HOSTGROUP_REGEX = Pattern.compile("%HOSTGROUP::(\\S+?)%");
 
   /**
    * Compiled regex for hostgroup token with port information.