Upgrade to OGNL 3.1.15

Fixes gh-1076

Author: kazuki43zoo

pom.xml

@@ -146,7 +146,7 @@
     <dependency>
       <groupId>ognl</groupId>
       <artifactId>ognl</artifactId>
-      <version>3.1.14</version>
+      <version>3.1.15</version>
       <scope>compile</scope>
       <optional>true</optional>
     </dependency>