Hi Devrim,
I'm not the expert here by any means; I only just got interested in this project when moving from ant to maven became something new and fun to try to put together. So, feel free to take my opinion for what it is-- just an opinion.
After some research, I found this thread awhile back which might contain helpful information:
In short, it says that the team does not want to use postgresql's version number in the artifacts. This would explain why the current releases of pgjdbc are not prefixed with 9.5, and are still at 9.4. It is my guess that the numbering of pgjdbc will stay on 9.4 for some time. But, I think this is sufficient evidence that having a hard dependency on a postgres major version is something that is not needed. So, I think I agree with your assessment. If you wanted a second opinion, Dave Cramer might be the best person to comment.
Additionally, I can verify that the if-block's make sense in the combined spec-file. I tried one of your pre-release specfiles on EL6 and had issues with "add_maven_depmap", "%files -f .mfiles", and the 2 "_javadir" files. I think the if-blocks are clean, and I approve your new changes with regard to making a combined specfile.
Regards,
-John
