Removing impl property for consistency with other apps and release script

Change-Id: I093e615a21c76b36eb8aa3539cfc2c25bb9ecda7
diff --git a/pom.xml b/pom.xml
index b7b87d8..7e2477d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -37,7 +37,6 @@
     <properties>
         <sadis.api.version>5.6.0</sadis.api.version>
         <olt.api.version>5.1.0-SNAPSHOT</olt.api.version>
-        <olt.impl.version>5.1.0-SNAPSHOT</olt.impl.version>
     </properties>
     <dependencies>
         <dependency>