[pom] Drop back on log4j2 due to jdk7 requirement

Author: hazendaz

pom.xml

@@ -173,10 +173,11 @@
       <version>1.2.17</version>
       <optional>true</optional>
     </dependency>
+    <!-- Don't upgrade to 2.4+ until mybatis switches to java 7 -->
     <dependency>
       <groupId>org.apache.logging.log4j</groupId>
       <artifactId>log4j-core</artifactId>
-      <version>2.4</version>
+      <version>2.3</version>
       <optional>true</optional>
     </dependency>
     <dependency>