
After switching to Eclipse Maven repository for pulling JGit lib, we have the problem that according to Eclipse release train the JARs have to be signed. That collids with our jgit patch for diff deserialization. To rectify that, add `unsign` parameter to maven_jar() function. Change-Id: Ib7bfa5d16f980a64b887d61a4b4ec325e6ffb0a1