remove duplicated version specification and use version from parent

Change-Id: If81ad08e9cf7995b68417e924a0e05df32a446bc

Author: ChristophEichhorn

cf-java-logging-support-log4j2/pom.xml

@@ -14,10 +14,6 @@
         <version>2.1.0-SNAPSHOT</version>
     </parent>
 
-    <properties>
-        <log4j2.version>2.7</log4j2.version>
-    </properties>
-
     <dependencies>
         <dependency>
             <groupId>org.apache.logging.log4j</groupId>

cf-java-logging-support-logback/pom.xml

@@ -13,10 +13,6 @@
         <version>2.1.0-SNAPSHOT</version>
     </parent>
 
-    <properties>
-        <logback.version>1.1.3</logback.version>
-    </properties>
-
     <dependencies>
         <dependency>
             <groupId>ch.qos.logback</groupId>