Switched orientdb to version 3.1.0. Removed comment related to jackson

version which is a direct declaration due to gcube-jackson switch

pom.xml

@@ -15,12 +15,8 @@
 	<description>Information System Bom is used to declare the version of dependencies shared across information system components</description>
 
 	<properties>
-		<orientdb.version>3.0.15</orientdb.version>
-		<!-- OrientDB version has impact on jackson and thinkerpop version. 
-				When OrientDB version is changed jackson and thinkerpop version
-				must be coherent with the one declared by orientdb -->
+		<orientdb.version>3.1.0</orientdb.version>
 		<gcube-jackson.version>2.8.11</gcube-jackson.version>
-		<thinkerpop.version>2.6.0</thinkerpop.version>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<serviceClass>InformationSystem</serviceClass>
 	</properties>