Build janusgraph-util with particular Janusgraph commit number

[tedhtchang]

Currently janusgraph-utils is build with Janusgraphv0.1.1. and with a workaround to run with different Janusgraph build. Ideally, we need to build janusgraph-utils with a desired Janusgraph commit.
The maven-scm-plugin is able to download a particular commit but still need to figure how to build Janusgraph first and then build the janusgraph-utils

     <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-scm-plugin</artifactId>
        <version>1.9.5</version>
        <configuration>
          <connectionType>connection</connectionType>
          <scmVersion>170f424852525d8cb7fd40754c5b8a3f8a68a3f6</scmVersion>
          <scmVersionType>revision</scmVersionType>
          <checkoutDirectory>${project.build.directory}/janusgraph</checkoutDirectory>
        </configuration>
     </plugin>