Unsafe HTTP URL in pom.xml

It seems JanusGraph initially tries to download packages from http://download.oracle.com before trying Maven central.
Downloading and building/running code from untrusted HTTP sources can lead to a security compromise where an attacker can setup a MITM (man-in-the-middle) attack resulting in remote code execution. The issue exists in your code in the following place: [pom.xml](https://github.com/JanusGraph/janusgraph/blob/3b71cd389cd1e9f04ea389962166eeb851683f8e/pom.xml#L167)

This issue was disclosed privately to Chris Hupman before posted here.

Start in pom.xml at line 167 and inspect the repository configuration that tries download.oracle.com before Maven Central. Verify how dependency resolution behaves after the change; done means the build no longer attempts package downloads over untrusted HTTP and uses secure sources.

Written by the indexing model from the issue text.