inherited scm block has wrong urls

[DavidLeoni]

Currently we need to replicate this in all subprojects, otherwise in the release.properties file strange urls like https://github.com/opendatatrentino/odt-commons.git/odt-commons appear (notice the appended /odt-commons at the end. Maybe it's a maven bug, don't know

    <scm>
        <url>${project.url}</url>
        <connection>scm:git:${project.url}.git</connection>
        <developerConnection>scm:git:${project.url}.git</developerConnection>  
        <tag>HEAD</tag>
    </scm>