upgrade spring version 3.2.18

pom.xml

@@ -99,7 +99,7 @@
         <java_source_version>1.7</java_source_version>
         <java_target_version>1.7</java_target_version>
         <file_encoding>UTF-8</file_encoding>
-        <spring_version>3.2.9.RELEASE</spring_version>
+        <spring_version>3.2.18.RELEASE</spring_version>
     </properties>
 
     <modules>