Bump OGNL from 3.2.14 to 3.2.15

To resolve #1648 , hopefully.

Author: harawata

pom.xml

@@ -148,7 +148,7 @@
     <dependency>
       <groupId>ognl</groupId>
       <artifactId>ognl</artifactId>
-      <version>3.2.14</version>
+      <version>3.2.15</version>
       <scope>compile</scope>
       <optional>true</optional>
     </dependency>